hd550的论坛贴

Here are two great critiques by Sycra of other folks works that cover the main issues concerning your images.

Gestures:
&index=21&list=PL88584D90667CCEDE
Drawing Form:
&index=2&list=PL88584D90667CCEDE

I believe way too much of your focus was spent on color, gradients and such rather than character action, form and anatomy. I think Sycra's videos will show you better than I could tell you here and give you some tips to really help.