Select the style of story you want to write. The mystery genre includes many subgenres, including everything from amateur detectives like Sherlock Holmes to private eyes like Dick Tracy. Determine your style early so you can know what types of details to include in your story, OCook writes.
Choose the point of view you will use to tell your story. Weigh the advantages and disadvantages of each type, including first-person and third-person perspectives. The decision "depends on the atmosphere you wish to project and the type of scenes you plan to dramatize," OCook writes. For example, you can't share a suspect's thoughts if you're writing first-person perspective for your protagonist.
Plan out a loose outline of your story to help guide you through the writing process. Build up to and unleash an effective climax by plotting situations full of suspense and drama. Work out any kinks before you start writing with your outline.
Create a protagonist who will appeal to readers and help carry the plot. Make sure your protagonist is ready to withstand a lot of action to uphold suspense in your story. Keep the principal character "uneasy, anxious, harried, in constant jeopardy," OCook writes.
Choose your antagonist, but keep his identity a secret to the reader until the very end. Let the reader guess at the murderer, for example, to maintain interest in the plot, OCork advises. Help the murderer hide himself by concentrating on telling the story and by making other characters stand out more.
Include red herrings throughout your plot. Sprinkle suspects, victims and inconsequential characters in your story to derail the reader's assumptions. Twist the plot by including minor personalities that help advance the story and throw suspicion off the real bad guy. OCook recommends giving "the least of your characters dignity" so readers can better identify with them.
Take the time to work on your story every day. Schedule a block of space in your day when you can focus entirely on writing your mystery. Devote yourself to telling your story, and make sure that "each day, your writing work comes first," OCook says.
Write a title that is worthy of your mystery masterpiece. Use the title to attract readers to your story. "Plan ahead," OCook advises, "in case you've just written the start of a series. You may need to tie in future titles to this one.
Stay confident and persistent when looking to sell your manuscript. Create a short proposal that tells potential publishers and agents about your story and yourself. Expect rejection, OCook writes, but don't be afraid to keep promoting your mystery until it gets accepted.