I believe, that we are here also to share our experience and I wanted to share mine.
I started with the rough idea of this girl walking slowly through the rushes in some kind of trance. I do not know what in hell I was thinking but I painted most of her first and then planned the rest of the illustration. No thumbnails, no sketches and no thinking about composition.
Do I have a screw loose or what? Probably.
I spent most of my time then to work out my mistakes and it was like chasing after my own tail.
Do not make the same mistake I did. Work with the idea, with sketches. Don't just dive into this blind rush like I do.
You'll save a lot of time ;P