This is from an interview with crime writer James Ellroy in the Paris Review,
"I begin by sitting in the dark. I used to sleep on the living-room couch. There was a while when that was the only place I felt safe. My couch is long because I’m tall, and it needs to be high backed, so I can curl into it. I lie there and things come to me, very slowly."
INTERVIEWER: What happens after the sitting-in-the-dark phase?
"I take notes: ideas, historical perspective, characters, point of view. Very quickly, much of the narrative coheres. When I have sufficient information—the key action, the love stories, the intrigue, the conclusion—I write out a synopsis in shorthand as fast as I can, for comprehension’s sake. With the new novel, Blood’s a Rover, this took me six days. It’s then, after I’ve got the prospectus, that I write the outline.
The first part of the outline is a descriptive summary of each character. Next I describe the design of the book in some detail. I state my intent at the outset. Then I go through the entire novel, outlining every chapter. The outline of Blood’s A Rover is nearly four hundred pages long. It took me eight months to write. I write in the present tense, even if the novel isn’t written in the present tense. It reads like stage directions in a screenplay. Everything I need to know is right there in front of me. It allows me to keep the whole story in my mind. I use this method for every book."