May I ask how you drew that? With a pencil (scanned and resized), a tablet, or a mouse? I ask this because I'm impressed with how much that pose breathes life into it.
I believe color and shading are good, with a few little nitpicks.
To begin with, you might want to consider some problems with few areas. For clarity, I drew some arrows pointing to a few areas on two different backgrounds:
The red means you will have trouble on other backgrounds.
The blue, however, are more of just something you want to watch out for when creating a background for her. Depending on the background, you could get away with those black lines, but of course it always helps to make those black lines appear not
entirely black (never use color #000000 for something like this), but a really dark shade of the current darkest shade of brown.
Overall, good job. Design seems to be done quite well in my opinion.