I think you have most of the anatomy down pat! It's just the perspective tripping you up. It just seems like her feet are standing on anything, and she's not grounded all the way. Don't get my wrong, because I have trouble doing it too .___.

(err, yeah, I took some liberties with the angling and some of the pose, but you should ignroe that if you don't like that.)
One other thing was that her hair didn't cover her head all the way. Well, her hair did cover her head, but just barely!
Also, her feat seemed a little too small. The length of a foot is usually the length of the forearm (elbow joint to wrist) it's not always, but that's the normal standard (at least that's how I learned it)
Overall, it's a cute character design ^^ You seem to know your proportions and you have a pretty nice grasp on anatomy. All that's left to work on is perspective, and refining your anatomy skills :3 ! Keep up the good work!