First off, drop the scribble style, you'll work ten times faster if you focus on quick lines over the scribble lines (I should know, I used to do the same thing).
Getting down to the actual piece of art, the proportions are all wacky, even for cartoon'ish proportions, they're pretty ridiculous. The body's way to big compared to the features, making the legs and arms look incredibly short. Moving on from that point, the arm holding the shield should be bent back more, so you can see the tip of the elbow from the right side of the shield. Finally, the pose is very boring, it could use some energy. Make the limbs take on more interesting shapes, give the face a better expression (is she feeling confident scaling the mountain? Scared?)
EDIT: Okay, added the image. I'm sure it's not the best, but it should get a lot of my points across well enough. Enjoy.