I'm timidly trying digital color studies, so I'm using just Steve Ahn's Ultimate Brush, with as minimal tricks as possible. The only gimmicks were the slight radial blur on the grass flying up.
Easily discarding the the old camera blur routine, the main idea was to draw on as few layers as possible with this no-opacity-change, minimal-width-change brush with no blending, just pick colors and draw. I did cave and put the background, foreground, lightning, and character on their own layers like a pikachump.
I also added the foreground grass at the last minute since the heavy clouds and dramatic purples made me think of a familiar color composition.