As the author of thirteen murder mysteries and counting, and a literary agent who represents a number of mystery authors, I keep a list of “musts” for writing a compelling mystery that really holds together. Build all of these points into your mystery novel and your book will be stronger for it. Make sure your sleuth has a compelling reason to want to solve the murder. Mysteries always work best when the sleuth has a strong, preferably personal reason, to want the murderer brought to justice. For instance, in my first mystery, Missing Marlene, Jane Stuart wants to find out who killed her son’s live-in nanny.