My biggest criticism so far is that there does not seem to be any real rhyme or reason to the shapes of clusters of pixels. I mean, there is, but the outlines are awfully jaggy and irregular, and could be cleaned up relatively easily. Also, the shading is somewhat pillowy and as a result the wings and the body appear to be on different planes.
I will take a crack at a proper edit to show what I mean when I am not at work.
Incidentally: where is this taking place and what is the scene surrounding the pose? The pose does not convey a particular story or action to me, despite it being a relatively unlikely pose (as opposed to simply standing or reclining, say.)
All that said, I think this piece has a lot of promise and you seem to be doing a good job of developing it.
EDIT:
Is there a reference for this image? I ask because if there is it will be helpful to compare and also might help explain the unusual drawing-a-bow/warding an attack pose. Incidentally I notice that that pose is not unusual for angelic characters, oddly:
EDIT (again):I am a doofus
Yeah, but just really for the wings.
I took some pictures from google (like a dress or something) but the only picture i still have, is this:
http://www.hd-gbpics.de/gbbilder/engel/engel5.jpg
