Goku - attempt #1 at digital painting

Usually, I'm more comfortable with cel-shading techniques, but I really want to learn digital painting and rendering. I'd love to do some awesome illustrations like the pros I see at conventions.

This attempt at digital painting was largely inspired by Jimbobox's Vegeta, so I guess some credit goes to him. I realize it might not be to everyone's liking, but as the title implies, the goal here was to learn a little bit about the technique from an artist I really look up to since 2013, not anything else. If my intentions hurt some feelings, I'm sorry about it, and I've learned my lesson. No harm meant.

I'm trying to become better, so if anyone has any tutorials or helpful hints in the following aspects of digital painting, I'd appreciate the help.

-Quick abstract backgrounds
-Digital painting and skin rendering in photoshop.
-Technique or brushes related hints
-Professional blending
-Color theory

Thanks in advance!