Sword: The sword is drawn very well in terms of perspective or "making it look really close to the viewer".

The front leg: It's bent backwards instead of forward leaving your character in a strange position. Maybe this could help you in terms of stances.

The hair- The shading in the hair looks like it was just thrown in to add some kind of detail, maybe if you pinpointed the individual strands and then added shading it would look better.

The back leg- I think it should be facing more forward, or at least the foot should. It seems like if you actually tried to stand in a stance like that you'd have to break your leg. And if you could, I doubt it'd be a effective stance.

The front hand- It isn't gripping anything, it's position as if it's holding something but it doesn't look like it. Is it because whatever it's holding is the same color as the glove? Also, the thumb looks kind of short.