Fist off, whats up with the white wash that seems to be going on?
your description says you scanned, but it looks like a bad photograph with a webcam or something.
If your going to document your work with a cam of some sort, you should give this tut a read, it's by NG's very own Art101
Anyway, moving on. You got some vibrant colors which is helping, but only so much. I think you should take some time to practice the color more.
Anatomy is a big issue here. Your proportions are all screwed to hell and you got bends in the arms that would have me thinking that the arms were Broken.
Take some time to learn some anatomy and some of the other basics of anatomy.
You should also try and work on something other than anime. Their are so many expectations over anime that it is best to get the art basics down and proper anatomy down before you go out and start breaking those rules.
On a last note. this really isn't that original, and that really strips away from the entire thing. When I clicked on the thumbnail, I thought "Oh great another Naruto fan piece" and to be honest, I could still consider it that. So Google some Character design tuts and try again, cause this could easily fall in to the sea of endless anime fanart.