Why should we sleep on it? This post discusses incubation, sleep, and dream theory! My own experience, words from a sleep psychologist, and a wacky experiment examining the creative process.

“sleep and dreams and creativity” by Rachel Olsen: http://rachelolsen.blogspot.com.au/2012/10/dreaming-and-creativity.html
My own experience:
So you remember how I was working on a novel and I just couldn’t finish it? Right, right, that was months ago. Well, I finally had a breakthrough!
I originally envisioned this novel in three parts, but currently only two parts of it work well. So I was thinking that parts one and two combined work as a standalone novel, with some revision.
But the problem that was to be solved was, at the end of part two, the heroine and her lover part on opposite sides of an intergalactic war. As enemies. So sad! And since I’m the kind of person who doesn’t deal well with sad endings (open that box of worms another day), this ending had to be fixed!