What To Keep Track of When You're Plotting a Mystery by Marilyn Levinson

Keep in mind all aspects of your sleuth's personal and professional life.

Don't forget to include updates in the lives of your sleuth's love interest, family, and friends.

Who are your victims and why were they murdered?

Who are your suspects and why are they considered potential murderers?

Make the most of the season (holidays, special events and celebrations.)

Always keep your setting in mind. Have a mental map of your town. Even better, draw one.

Make a list of all your characters and make sure you don't change their names midstream. (Don't laugh. My editor caught me putting Sammy, my real cat's name, in the manuscript instead of Smoky Joe.)

Most important: as you write, keep track of your days so that Friday follows Thursday. And of your weeks, so that you know if you're still in April and not yet in May. It will save you time later on.

Be careful when you name your characters. Don't start too many names with the same letter. Vary the number of syllables. Consider that some readers might confuse names like Don and Bob. Don't end all of your female names in a or ie.

Keep track of where all your suspects are at the time of each murder.

If you're writing a series, be sure to vary your methods of committing homicide. Whatever the method, the details may be few, but those you include must be authentic.

Have your sleuth acquire information in various ways. Consider that some sources of information may not be accurate or truthful.

Create secrets for your characters. Whether or not they are part of the murder investigation, secrets intrigue readers. Unearthing secrets may provide a piece of the investigative puzzle. They may also be used to send your sleuth in the wrong direction entirely.

Consider your characters' emotions. Readers love to cheer your sleuth on. They love to see her nemesis get put in her place.

A love interest adds a dimension to your book, but don't let it overshadow the mystery.

Red herrings and misdirection are necessary to maintain suspense.

Even if your protagonist is an amateur sleuth, the police will have a place in your book. Don't make them out to be idiots. While your sleuth may not have access to their labs and equipment, he/she may know the victim's family, friends or neighbors, who may be more willing to talk to share information.