sup /ic/

Help me out with shading and highlights and such, would you? I really suck at colour theory, so I'm trying to nail my shading skills/ knowledge. I've been staring at this for most of today, and I think I need some fresh eyes to look at it.

Included a close-up of the face because when I shrank it right down, the face looked completely different, and it changed the look of the entire piece.

tl;dr - character base design, need help with shading plz.