Ohhh, your art looks really good! If you want a suggestion, though, then I'd perhaps say you could widen the shoulders out a little more (Very slightly, I mean), if that makes sense? If it doesn't, let me know. I can give an example, maybe, or explain it better.
But that's about all I can think of so far. :{o Once again, it looks pretty nice nonetheless - Style seems pretty smooth. ^^
EDIT: Tailgate kinda explained what I said as well, by the way.