5 Tips for Writing a Detective Novel Series

There’s nothing like a detective series for some much-needed escapism. Whether you’re a writer of crime fiction or a cozy crime enthusiast, you’ll know that these novels are exemplary in keeping a reader’s attention—you only need to look to bestseller charts to see crime fiction leading in sales.

So what is it about these series that makes them so devourable? And how do you apply the techniques of bestselling detective novels to your own story?

In this article, Emylia Hall offers writers (and readers!) five tips for crafting a crime or detective novel series. Emylia explores how to write memorable detectives, immersive settings, practical and accurate police procedurals, and how important it is that, ultimately, you’re as hooked on your story as a reader would be. With plenty of contemporary examples, you’ll find the perfect reading list to get you inspired, ready to plot and plan your next novel.

Emylia Hall is the bestselling author of the six-book cozy crime series, The Shell House Detectives, and four women’s fiction novels. Emylia’s debut novel, The Book of Summers, was a Richard and Judy Book Club selection, while the first of her latest series, The Shell House Detectives, was a Kindle Top 10 bestseller and has been optioned for television by Playground Entertainment. At The Novelry, Emylia coaches cozy crime and mystery, literary fiction, and reading group fiction.

The latest installment of The Shell House Detectives, The Death at the Vineyard, is available now to preorder from booksellers and online. To celebrate her publication day, Emylia shares her love for the genre with us in the form of these brilliantly insightful tips.

Tips for writing a detective novel series

Do you remember the first detective series you fell in love with?

For me it was the long-running TV drama Inspector Morse, based on the novels of Colin Dexter. It was the 1990s and I was a teenager growing up in rural Devon. I had next to nothing in common with the grumpy, middle-aged detective investigating murders in an elegant university city. So what did I see in that show?

The mysteries were complex, crediting the viewer with intelligence, and the solutions often bittersweet. The lead, played by John Thaw, was charismatic—for all his high and mighty, ale-swilling ways. He had a romantic edge and was compassionate and emotional beneath his curmudgeonly exterior—not to mention the brilliant foil he had in steadfast Sergeant Lewis. The theme tune? My God, the theme tune. Its haunting strains spoke to something in me that I didn’t even understand. And, somehow, Morse felt cozy. Not on the face of it—there were gruesome deaths and desperate, twisted individuals—but with Morse at the helm, no matter the case, it felt like a safe passage through turbulent waters. More often than not, I watched the show wedged between my parents on the sofa, with something good to eat. In later years, visiting my childhood home as an adult, I’d turn up brandishing the 33-episode boxset, and Dad and I, spoilt for choice, would settle down for a late-night viewing.

Without that early passion for Morse, I wouldn’t be writing crime today. And while my Shell House Detectives mystery series has a different tone, I approach the writing desk with a deep appreciation for the power of charming leads, atmospheric settings, mysteries that pull on the heartstrings, and the myriad complexities of human nature.

When I started writing The Shell House Detectives, it was the first in a three-book series. I didn’t have a grand plan. I hadn’t mapped out character arcs or cross-series overarching narratives. I simply felt that my fictional setting of Porthpella—a beachside community in West Cornwall—could offer up lots of stories, and my core cast felt like an interesting enough gang to return to time and time again. At that point, anything I knew about series writing I’d picked up largely by the osmosis of watching and reading.

As I write this piece, The Death at the Vineyard, the fourth in my series, is set to be published. I’m working on the copy edit for the fifth book, while also diving into the first draft of the sixth. I’ve learned so much in the last four years, changing the way that I plan novels, finding my flow, and keeping a firmer hand on the tiller throughout the process. I’ve also learned a lot about the nuts and bolts of series writing, and consider it an ongoing apprenticeship.

In that spirit, here’s some practical advice and some personal field notes.

1. Make sure your detectives are good company

Whether amateur or professional, your detectives will be carrying the story as well as the investigation. They need to have enough depth that the reader wants to stay in their company, book after book.

There are so many elements at play in a detective novel—the simple question of ‘whodunnit?’ can, of course, keep us turning the pages—but if the case-crackers themselves are mechanical, you’re missing a big trick. We want the reader to care. To feel a detective’s commitment, frustration and hope. To ride the peaks and troughs of an investigation alongside them.

Whether it’s Ann Cleeves’s unconventional and disarming Vera Stanhope, Ian Rankin’s dour maverick John Rebus, or Susie Steiner’s chaotic and whip-smart Manon Bradshaw, in each case we’re in the company of someone compelling. And, however flawed, ultimately lovable.

The richer your character, the greater the opportunity for interesting storylines. Think about the texture of their past and the complications of their present. What weights are they carrying? How deeply can we entangle them in a case, on a personal level as well as professional? To borrow from Miller Williams’s beautiful poem ‘Compassion,’ consider ‘what wars are going on down there where the spirit meets the bone.’

Consider, too, who the perfect foil might be for your detective. Who can serve as a sounding board or kicking stool, perhaps even offer the crackle of chemistry?

I tore through Elly Griffiths’s Ruth Galloway series, and above all, it was the on-off romance of Ruth and Harry that kept me reaching for the next book. The same for the TV version of Robert Galbraith’s Strike and Robin. Big emotions aside, a partner/sidekick also has practical uses for an author; they allow you to share your detective’s thinking in a way that feels natural. As they recap, question, and posit, the reader is an eavesdropper—and any exposition feels natural.

When my sleuths Ally and Jayden meet, they’re each adrift in different ways. Ally, a natural introvert, was widowed a year ago; while she’s always been happy in her own company, some days life feels as empty as the beach at low tide. Meanwhile, Jayden has relocated to Cornwall after leaving his job in the West Yorkshire Police; he’s mourning a friend and, in some ways, the job. Through their first case they each find their footing and forge a unique bond, giving one another something they didn’t realize they were missing. And while they’re an unlikely pairing in some ways—Ally is twice Jayden’s age—they share a compassionate outlook and a commitment to never looking the other way. Those values drive all their investigations.

Unless you’ve already decided the length of your series—a trilogy, for instance—then you might not know the exact shape of your central characters’ arcs, and you’ll want to stay nimble. The Shell House Detectives series started as a three-book deal, and I was already working on the third book before the first was published. While I was traveling hopefully, I knew more books were far from guaranteed, so I planned the ending of book three so that it could work either way. I wanted to offer a satisfying resolution for Ally and Jayden, but also leave the door open for future stories. I had in mind the last line of A.A. Milne’s The House at Pooh Corner : ‘But wherever they go, and whatever happens to them on the way, in that enchanted place on the top of the Forest a little boy and his Bear will always be playing.’

As it happened, by the second draft of The Rockpool Murder I knew the series would be carrying on, so I slightly pulled back on certain story elements, untying a couple of bows along the way.

Louise Penny’s Three Pines series, starring the wise and optimistic Armand Gamache, is at 19 books and counting. Penny is quoted in the Seattle Times as saying: ‘As far as I’m concerned, it will never end until I end. He (Gamache) will be buried with me.’

Writers have all sorts of reasons for calling time on a series, and sometimes the choice isn’t ours to make. As in real life, the only certainty is that, at some point, the music will stop. So make sure your detectives have given the dance everything.

2. Pick a sustainable setting

The setting for your series is a big part of how readers will connect to your stories.

Think about the kind of atmosphere you want for the world you’re building—and in turn how that translates to the reading experience. When I reflect on some of my favorite crime series, the setting looms large—as well as the pervading feeling that comes with it. Abstracted snapshots push in: a boathouse; a cobbled alleyway; a salt marsh. I read to be transported.

Clare Mackintosh’s DC Ffion Morgan series plays out in the border country of England and North Wales, where close-knit communities hold deep secrets, and incomers underestimate the rugged landscape at their peril. William Shaw’s DS Alexandra Cupidi series unfolds in Dungeness, a stretch of Kentish coastline that’s as bleak and haunting as it is beautiful. Jacob Ross’s Michael ‘Digger’ Digson series plays out on the lushly and lyrically evoked Caribbean island of Camaho. When a place is expertly rendered, the story becomes inextricable from its setting, and the reader experience is all the more immersive.

I want my Shell House series to feel escapist and transporting, and the West Cornwall setting is so important here. I strive to conjure the beauty of the place, but also the darker side: how the weather can turn on a dime, storms blowing in—literal and metaphorical—and wreaking havoc; how a location can feel perfectly secluded one minute, then lonely and vulnerable the next. But while I leverage the landscape for dramatic effect, overall, I want a reader’s association with Porthpella to be warm and positive, like when you think of a beloved holiday destination. Sure, there’s murder, but... You still wish you were there.

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Setting also has a bearing on the kind of dramas that are likely to erupt in such a place. Arguably, wherever people go, trouble can follow, but certain locations lend themselves more naturally to particular crimes. Is gang violence likely to come to a head in a quaint village? Well, possibly, but an urban environment is more likely. In fairness, if you look at violent crime rates, an urban setting is more likely across the board. So... Enter poetic licence.

In my series, the influx of second-homers and tourists ensures an ever-changing population—as well as rich territory for conflict. Of course, suspension of disbelief is a factor. No holidaymaker in their right mind would choose Porthpella, given the murder rate around those parts. But so long as other aspects of the stories ring true—the characters, the landscape, the mysteries themselves—then we’re granted, I believe, some leeway in that department. And the fact that my series sits within the broad church that is the cozy crime genre, I consider that licence to lean into the leeway even further.

While setting can be key to the appeal of a series, Lee Child’s Jack Reacher is a wanderer, and a major part of his identity is to not lay down roots. From a writing perspective, this means we never know what we’re going to get. Chicago? Colorado? Hamburg? For the author the possibilities are endless, and for the reader, every novel feels pleasingly like a road trip.

3. Keep a log of practicalities

Writing a series means taking responsibility for a fully populated, ever-changing world.

Unless you’re deliberately writing outside of usual lines of time and space, you’ll need to be aware of the passage of time, the turn of the seasons, the limitations of geography, and how the lives of your recurring cast evolve between books. Having a decent handle on this is not just good housekeeping but is also creatively useful; ideas for personal storylines and subplots will emerge in a way that feels true to life. Before I start writing the next novel, I love sitting down with a notebook and figuring out what everyone’s been up to in the intervening months.

One of my reader reviews said, of a future book, ‘I can’t wait to find out what happens next’—which was a great reminder of the importance of subplots for my recurring cast. Another review described The Harbour Lights Mystery as ‘Agatha Christie meets Coronation Street,’ which not only did I love, but again, it helped clarify what I want the series to be. Not just a murder mystery, but a lovely big slice of Porthpella life. As part of my planning process, I also consider how the season can play into my story. And I look at the locations I’ve used before, considering where I might center the story next, so it feels ‘the same but different.’

The passing of time can be sobering. In the first book I wrote that Ally’s little dog, Fox, was ‘nearly ten.’ At the time I liked the idea of him being no young buck, but honestly? I didn’t consider the consequences. By book six, two and a half years will have passed. Fox is surely slowing down. At a recent book event a reader came up to me afterward and said, her face grave, ‘I’m worried about Fox. He’s getting old.’ Meanwhile, a friend has told me I cannot, absolutely cannot, let Fox die. Perhaps Ally’s immortal dog will be another bit of ‘cozy’ poetic licence...

Series writers also need to consider the fact that people may read the books out of order. By the time I was writing the follow-up to The Shell House Detectives, I’d learned the art of the subtle recap, a way of conveying pertinent details of past investigations and relationships without pulling too much from the present, nor straying into spoiler territory. Naturalness is key, so I try to drop in these summaries as character reflections, when it makes sense for someone to be bringing a past event or relationship to mind.

Early on, I decided that while there would be an element of rose-tinting (it is a cozy mystery, after all), I wanted to write my characters with as much truth as possible. So, over the course of the series, they learn, they age, they remember.

I try to keep a note of the most seismic experiences I’ve put them through in case that colors their response to something similar, months on. Every so often I forget something fundamental, though. I was halfway through the first draft of The Death at the Vineyard  before I remembered that Jayden had saved an important person’s life in the last book, and neither he nor that person would be likely to be trotting through their interactions in this next book without occasionally thinking about that point of connection. Not sure I deserve a pat on the back for that, but still... Nice catch, Emylia.

In John Yorke’s brilliant Into the Woods, he writes: ‘Every great story in drama forces the protagonist to confront their needs and flaws and if a character does overcome them they’re complete—but dead. The golden rule in series is that the needs/flaws should either be overcome fleetingly, or possibly never, but certainly not until the final episode.’ While Yorke is writing of TV, the same is true of novels.

So while my characters learn, it’s only to a point. And frankly, like most human beings, they also fall back into the same traps and make the same old mistakes. In the first Shell House book we meet PC Tim Mullins. He’s laddish, cloddish, likes being a big (or so he thinks) fish in a small pond. He’s also one of my favorite characters to write because he’s ripe for redemption. Every small step that Mullins makes—in compassion, tact, generosity, bravery—is actually a giant leap. But I know I need to keep an eye on this, because if he evolves with too much pace, something will be lost. We need his (relative) idiocy in order to retain the essential character dynamics.

As part of the planning process for the sixth Shell House Detectives book, I made a list of all the victims through the series so far, noting their age, gender, and circumstances of their death. I did the same for the perpetrators, including their motivation each time. I then looked at the themes I’d addressed in each novel. This appealed not only to my imagination (I’m a detective going over old case files!) but also my semi-officious nature. Above all, it’s a useful way to avoid repetition and make sure future choices are studied.

4. Keep your own interest firing

In Into the Woods, Yorke writes: ‘Successful series, then, are built on the backs of certainty, of predictability and of the audience’s loves—on their wish to be there too.’ But in delivering ‘certainty’ and ‘predictability’ for the reader, it’s important that, as a writer, you don’t feel like you’re simply going through the motions. Indeed, the uncertainty and unpredictability of the writing process is where a lot of us find the magic.

The last thing we want is a ‘here we go again’ vibe, because at best it’ll dent our enjoyment in the writing, and at worst that flatness will seep into the finished novel. Your series will slump. The moment things start to feel mechanical or repetitive, hit pause. Think actively about how you can breathe new life into both your process and your feelings for the story. Some writers, for instance, alternate their series writing with other projects. Or decide to make that next book the last outing...

Martin Edwards, writing in Howdunit, a collection of essays by members of the Detection Club, says:

Arthur Conan Doyle famously killed off Sherlock Holmes at the Reichenbach Falls before succumbing to public pressure (and handsome financial inducement) to resurrect the sage of Baker Street. Agatha Christie had her fictional alter ego, the writer Ariadne Oliver, tire of her Finnish detective, just as Christie herself became frustrated with Hercule Poirot.
—Martin Edwards

For my part, I’m still all in with my Shell House gang. I’m on book six and I hope to keep writing them as long as my publisher wants to keep publishing them. The setting is pure wish fulfillment; writing that run of coast, those dunes, never grows old for me. With every new novel I make sure I take myself off on a self-styled writing retreat. I rent a cottage, out of season, either on my own or with a writer friend. It’s where I catch up if I’m behind schedule or try to forge ahead (usually the former). It’s also a huge part of my pleasure in the process, this act of creative immersion sustaining me for weeks afterward.

By now, my characters are like treasured friends. Somehow, writing them over time, through different seasons of life, through highs and lows, makes them feel more real to me than ever. But as much as I love hanging out with the core gang, what excites me most about every new outing is the opportunity to create new characters and figure out what makes them tick; to understand the darkness in their hearts and their brightest hopes.

Meanwhile, every new crime, and the investigation thereof, is a puzzle to solve. It’s the part of novel writing that fires my brain like no other. It’s one thing for me as the author to decide who the killer is, and then work through that motivation, but quite another to present it in such a way that my sleuths can plausibly figure it out for themselves.

While every new novel has its own challenges—it’s a fool’s errand going into it thinking you’ve already got it licked, just because certain aspects are well-established—I do take satisfaction in the refinement of my own process. By now I’ve figured out what works for me, and what doesn’t.

With every new book, I know to start out by asking myself the following:

• What’s the set-up?
• Who’s the cast for this new story, and how do they connect to one another?
• How can I give the crime an emotional rooting? What themes am I interested in?
• What line will the police be following, and what’s the way in for Ally and Jayden?
• What’s happening in the personal lives of my core gang and how does that affect the case?

I fill notebooks with freewriting, posing ever more questions. I go deep on character, as that’s where my plot always comes from. Then I put together a story outline for my editor. I won’t know everything at that point, and I’m fully prepared for it to shift in the writing—indeed, I want it to—but I know whodunnit. And I know how and why. Once I’m into the writing, I’ve now learned not to be destabilized by the fact that I might not know what happens more than a couple of chapters ahead.

As E.L. Doctorow said: ‘Writing is like driving at night in the fog. You can only see as far as your headlights, but you can make the whole trip that way.’ I also know there will undoubtedly come a point where I’ll scratch my head and ask, ‘BUT HOW DO ALLY AND JAYDEN ACTUALLY FIGURE IT OUT?’ I’m after that piece of breakthrough thinking as much as my sleuths are. It also helps that, over time, I’ve assembled my experts and I have Police Constable and CSI contacts on speed dial. While my main concern is serving the story, knowing I can fact-check with the professionals is always reassuring.

No matter how much planning and forethought goes in, there invariably comes a point in the writing where I think ‘I can’t do this.’ Where making the whole thing hang together, against my deadlines, feels like an impossible task. But I know, too, that a temporary loss of faith is part of the process. So, I give myself a stiff talking to and get on with it.

If you ever feel your enthusiasm waning, perhaps remind yourself why you’re writing your series in the first place. Why does it matter to you? What are your core tenets, for this world of yours? Here I think of P.D. James’s words, doyenne of the detective series, in The Private Patient :

The world is a beautiful and terrible place. Deeds of horror are committed every minute and in the end those we love die. If the screams of all earth’s living creatures were one scream of pain, surely it would shake the stars. But we have love. It may seem a frail defence against the horrors of the world, but we must hold fast and believe in it, for it is all that we have.
—P.D. James

Love drives my two Shell House sleuths, and it drives my writing process too.

5. Learn from reading

My last tip is to immerse yourself in crime series. As well as learning practical aspects, you’ll also gain a lot emotionally because there’s no better way to figure out what you want from your own series than by understanding what you love in other people’s.

Whether on the page or on screen, the best crime dramas are somehow as reassuring as they are invigorating. Just as there’s satisfaction in wrongs being righted and justice being served, there’s comfort in experiencing that feeling in the company of a detective you know and love.

My favorite new series discovery is Kate Webb’s DI Lockyer mysteries. Set in rural Wiltshire, Lockyer and his partner Gemma investigate cold cases. The writing is atmospheric, super smart, and full of warmth, while the cases are always emotionally stirring.

On the TV side I really love the Belfast-set drama Blue Lights. It follows both rookie officers and old-hands, and while it’s gritty and unflinching, offering what feels like an authentic window into contemporary policing, there’s such a kindness and grace to the portrayal of the characters and their complicated lives that I’m often moved to tears.

Hungry for more recommendations? Here, some of our writers and editors at The Novelry offer their favorites.

I adore Tana French’s Dublin Murder Squad. I love how each book features a different member of the murder squad as the main character. It feels seamless and fresh to move between them; as a reader, you start the next novel with some familiarity and preconceptions about the character that are swiftly shattered by inhabiting their perspective fully.
—Katie Khan

Character always pulls me in, and I’d say that’s true of all series I’ve enjoyed. Case Histories by Kate Atkinson is my favorite. In Jackson Brodie we have a fulcrum with a brilliant backstory of his own but who facilitates an incredible cast of characters in exceptional circumstances. Kate Atkinson also has a penchant for returning characters, not just Jackson.
—Amanda Reynolds

I think writers can learn a lot from TV drama series. I use them all the time as examples. Happy Valley is another slice of Sally Wainwright genius. As a general point it’s definitely character that gets me over plot, too. I rarely retain the (often rather convoluted) actual crimes—it’s the dynamics between the main players I love and remember. Robert Galbraith is a good example of this—I’m really reading to see when Strike and Robin will finally get together. Unforgotten is another great series. Again, the detective partners are the best thing in it! And back to books, I also like Lucie Whitehouse’s crime series, which starts with Critical Incidents. The down-on-her-luck MC feels very real and relatable. And I like the premise that she’s had to reluctantly go home to Birmingham where she grew up, which gives the whole thing depth and complexity.
—Kate Riordan

For TV, Veronica Mars! An outcast teen girl (played by Kristen Bell) investigates the murder of her best friend, while helping with her PI father’s investigations and her classmates’ problems in an uber-wealthy California neighborhood. Dark content and themes, but tonally the show is also very funny, and you get satisfaction from seeing Veronica outsmart the people around her.
—Elizabeth Kulhanek

Scott and Bailey. The relationship between two female detectives is what really kept me watching this—learning about their lives as they solve crimes was very satisfying.
—Alice Kuipers

My top picks: the Ruth Galloway mysteries by Elly Griffiths. I was obsessed with these over the summer and read them all one after the other. It’s not the mysteries, it’s the love story that had me hooked. Also, the Malabar House series by Vaseem Khan. I just love these so much. Set in 1950s India, with India’s first woman police officer (actually—historically, she isn’t, but that didn’t ruin my enjoyment) and her relationship with an English criminalist. So many issues at play in this series. Volatile political situation, race, sexism, and a relentlessly clever heroine battling against the odds. She’s also very clearly on the spectrum, so the relationship is really difficult for her and so touchingly portrayed. It’s always the characters that make a series. The Kamil Rahman series by Ajay Chowdhury. Again, it’s the relationship going through this that I can’t get enough of. And the DC Morgan series by our own Clare Mackintosh. And obviously The Shell House Detectives! Goes without saying...
—Gillian Holmes

The fourth book in the Shell House Detectives mystery series, The Death at the Vineyard, will be published on November 15, and you can write your novel with one-on-one coaching from Emylia Hall when you join us on a writing course with coaching at The Novelry.

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