J. Mark Bertrand has a two-part interview on writing and shifting genres on Boxing the Octopus, which looks like a blog I should follow. Here are a couple quotes:

I don’t believe in “writing what you know,” but I do think it’s sound advice to write what you’re good at. For me, that’s turned out to be crime. The art of storytelling doesn’t change from genre to genre, and I’m more interested in telling a good story than a good genre story, if you see what I mean. The conventions are there, and for the most part I respect them, but at the end of the day I’m making use of the genre to tell a certain kind of tale about the detective as existential seeker and skeptic.

From the second part, Kathryn Paterson notes, “I find your suggestion of writing a 50-paged treatment prior to drafting to be daunting, but fascinating.” Mark replies:

In the film industry, a treatment is a summary–more detailed than a quick synopsis, but not yet a fully realized, scene-by-scene script–that communicates the rough contours of the story. Some are more detailed than others, but since Dan was convinced the problem with most of us young novelists was that we didn’t know our stories well enough, he recommended writing a fairly detailed treatment before starting. For writers who don’t like to stick with an outline, this advice can be liberating. Writing the treatment helps you to discover the story.