I know exactly what you mean about "seeing" before you write. I usually let my mind dose off into a daydream about the subject in which i'm going to write about. When the capacity in which my memory for what I was daydreaming about becomes full, that's when I start to recap and write those things down. It's a repeating process after that... It's really a matter of how much time you have at that point, but then again, time usually gets lost in all this... That's when the Magic Happens.