/ic/ - Artwork/Critique

I drew this months ago for a drawfag thread on /v/. I didn't felt like actually finishing it until now, but whatever.
It would be nice if somebody could help with the proportions of the arms (especially the deltoids), the shape of the pectoral area and the upper leg muscles before I get to draw the actual thing.
Also, I'm want to draw him a hat and some pants (or maybe something else) like in the reference but I don't know what kind of shapes/texture should I apply.