Honestly, most of the issues I see with your art are things that are improved by practicing. Anatomy, lighting, backgrounds, all stuff that only improves by drawing more.
Some one pointing out your flaws does help you pick out those flaws for next time, but all you can do to fix them is to keep drawing. I know it's really frustrating, and I struggle to get any kind of criticism, good or bad, but that's pretty much the only solution. Keep drawing, if you get criticism, you get criticism, if you don't, you keep drawing anyway.
Projects-Dev
been there.
minichou
Got any tips?