Did a little edit. In the meanwhile, you got lots of useful replies, heh...

This work is looking good, i like the shading and the face and hair. It's moving in a great direction, should look great in the end. I specially like how it has a few anime subtones while freeing itself from the "anime look" template, personally i'm tired of that worn look (SF concept art was always somewhat far from that, and i loved it).
The main thing i did was fix the shoulder length. I added some lines for muscle form and definition, but they're just my interpretation, hope they're not so messy that you can't make it out.
Oh yeah, and basically what baccaman said is the basic thing you'll have to do anytime to get consistent looking anatomy, not wonky one. And going back and redoing wrong stuff from the start is what separates a mature artist from one who has yet to reach that point... (something i've only relatively recently come to have a grasp on)