This is what I do in the middle of the night.
The outline was already there. I looked at it in passing and then pulled out my tubes of gouache paint and this is what happened. Sometimes I think some entity is in control of me because this just happens, and it usually happens late at night. There is no plan, no intent, just pure action. And I always flow with it.
If it feels right, follow it. It's your intuition at work.
Simplicity is the removal of the useless and the unnecessary--source unknown