A cozy is a mystery which includes a bloodless crime and generally contains very little violence, sex, or coarse language. By the end of the story, the criminal is punished and order is restored to the community.
The character solving the crime is often an amateur sleuth who becomes involved because of personal reasons but it is also possible for the character to be a professional: police officer, medical examiner, or private detective.
Many cozies invite the reader to solve the crime first. In those instances, clues should be evident and fair. Red herrings (apparent clues which distract the reader) may be included and all the suspects might appear guilty along the way but these falsehoods should be explained by the end. The missing candlestick was taken by a child for a school project; the averted glance which suggested guilt actually represented guilt for snacking at midnight.
The novels of Agatha Christie and the mystery stories in Woman's World are examples of cozies.
The main character in a cozy is the good guy (or gal). This person uncovers the criminal through an emotional or intellectual examination of the scene, suspects, and clues. The main character may tell the story in first person or the story can be told in third person.
The reader will want to be able to identify with the main character who should be likeable and whose faults are present but socially acceptable. For example, she may "always be late" but she shouldn't be a heroin addict.
Cozies often emphasize the positive. If your main character is always late, that fault may in fact prove to an important factor in solving the case.
The victim in a cozy should not be someone who is terribly missed. Cozies are, for the most part, feel good stories. Murder is wrong, but someone had to die for the plot to get underway, so at least the victim was the rich uncle that nobody really knew.
The criminal in a cozy is usually motivated by human traits of greed, jealously, or revenge. You won't find many serial or thrill killers in cozies. The criminal may commit a second crime during the story but again any violence should take place between the lines and not on the page.
Supporting characters in a cozy can be eccentric, exasperating, or entertaining. They don't have to be likeable but none should be so outrageously evil that they might cause the reader to stop reading. These people include the suspects (of whom the criminal is actually one), innocent bystanders, and those who may help the main character.
Then there are the cops. In real life, the police would seal off the murder scene and run the investigation. Cozy readers will accept that not happening so long as you give them the slightest reason for suspending their disbelief. Perhaps bad weather is keeping the police at bay or the entire department is off on a team-building exercise.
While Agatha Christie popularized the small English village as a setting, cozies can take place anywhere.
Typically, a cozy has a small setting so that the pool of suspects is limited and relationships can be developed. Since the main character does not usually have access to forensic laboratories, the solution of the crime depends on talking to characters who all know each other.
For the sake of simplicity, you may decide to set your cozy wherever you live. If that happens to be a bustling city, shrink the scope to focus on a single apartment building or workplace.
Cozies can take place at any time although those occurring in the past will be considered historical mysteries unless they align with Agatha Christie environments. Weather is often bad, isolating the cast of characters from outside assistance or escape.
The cozy is often a puzzle where all the pieces are available for assembly, even if the one which points at the killer needs to be flipped or examined more closely.
The precipitating crime either occurs before the story starts or soon after it begins. The main character becomes involved (happily or not) and sets out to solve the injustice.
As the sleuth gathers clues and gossip, there may be a threat which increases tension. There may also be fear that a second crime might occur, and it might.
The cozy is not a roller coaster ride as much as it is an examination of human frailty. Instead of unexpected plot twists, cozies are known for surprising revelations.
In the end, the main character -- and justice -- prevail.
While graphic sex is out, romance may play a part in the cozy. If the romance starts to overshadow the mystery, however, the story has crossed over into another sub-genre of mystery: romantic suspense.
While most cozies feature amateur detectives, you can write a cozy with police officers or private investigators. You must still focus on personal touches and should downplay realistic aspects of the crime and investigative practices or you'll be crossing into the police procedural or PI sub-genres.
The cozy elements may also be transferred into the future. While most mystery readers are not open to mixed genre SF-Mysteries, SF readers are.
The most important exception, of course, is the one that you might bring to the story. Most rules can be bent and some can be broken. As long as you remain true to the overall sense of the cozy, you do have some leeway with your characters and plot.
Attend Malice Domestic, the primary cozy mystery conference.
Subscribe to the DorothyL mailing list at http://www.dorothyl.com/.
Join or at least visit online the Mystery Writers of America (http://www.mysterywriters.org) and Sisters in Crime (http://www.sistersincrime.org/).
Read Writing the Modern Mystery (Barbara Norville) and Amateur Detectives: A writer's guide to how private citizens solve criminal cases (Elaine Raco Chase and Anne Wingate), both published by Writer's Digest Books.
The following publications accept cozy short stories. All but Mysterical-E pay.