Working on "The Water Castle", I got to a point where I really didn't understand my own story and was becoming afraid that I'd screwed it up, and realized that for me writing is like jumping off a high board before I look to see if there's water in the pool. I just have to trust the process, and launch myself into flight, knowing that someday I will land in grace and beauty.
This probably makes more sense if you realize that I am a deeply subconscious writer. Virtually everything I write is a total hipshot, though I may do a lot of research, planning or explicit prethinking up front. Once I begin keyboarding, I'm lost in the story, wondering what comes next. "Following the headlights", as Bear says quoting E.L. Doctorow.
Update: It's early -- specficrider just pointed out that I'm essentially quoting she and I in our brand new IROSF article anent following the headlights.