One question that comes up in my writers' groups (both online and real-life) is, "Can you help me figure out what my genre is?" Sometimes the query is disdainful, "Because everybody knows you have to pigeon-hole masterpieces, or else the stupid publishers won't publish this brilliant work."
Knowing your genre is critical. (So is telling a good story, and having a whole lot of luck. Those are subjects for a different post.)
Many writers think figuring out a label for their fiction is beneath them. Like labeling is the job of the editor or publisher or crit partner. Nope. Genre hunting is an author's job. A writer absolutely has to know what she's writing, masterpiece or not. Oh, unless an author is really writing literary fiction, don't call the project "literary".
How does an author find genre if she's writing genre-straddling fiction? We had this discussion about a novel in a crit group once (certain identifying factors have been changed). So this particular story was about military involvement in high tech weaponry, using time travel to ancient Rome. There was love-story subplot, and mysticism.
What's the genre?
Here were the crit group's suggestions.
First narrow down the genre to a mixture of two or three good guesses. Guess according to plot, (not character or environment, and certainly not according to voice or style.) Rome, for example, is a locale, not a plot, so Rome won't be important in the genre research. What about the romance and mysticism? Sprinkling doesn't define a genre, so forget about romance and mysticism. For this novel, the preliminary genre blend turned out to be "military time travel" fiction.
Now comes the hard work: There are few examples of cross-genre "military time travel" fiction (I think?). Maybe the stories don't exist, or perhaps the novels are labeled something else. But there are zillions of pure military fiction stories and billions of pure time travel novels. These pure genres must be read. Best-selling examples of both should be studied. Classics in the pure genres, if they exist, should also be read.
These books may ultimately lead to the discovery of true "military time travel" tales. The idea is to build a private list of "If you enjoyed this not-yet-published novel, you will also like X and Y and Z."
Studying published works related to the "military time travel" piece, will, at a minimum, make for a better writer. It may also give the unpublished author the confidence to write an editor, "My book is a military time travel fiction."