Thank you! I'm just learning how to draw pixel-art and all advices, suggestions are have great importance for me. 
It's really great 
Only suggestion I could make concerning lighting is the bow's string. As a straight line, and with the light source at a few meters on the left like it seems to be, it would reflect the light the same way along all the string. Currently it looks like it's a thin metallic band reflecting some light coming from the left shoulder of the viewer.
Anyway she's wonderful, love it !
I would suggest a bit of dithering to smoothe the shades and lights, but it still looks amazing!
Her stomach looks like one of those packaged sausages.
But yeah, it's a good piece.