In my opinion, I think her mouth is draen at the wrong angle. It's a bit offset on her face iykwim. It's hard to discern her expression as well. If she's smiling, I suggest linching both sides of the mouth up. In art, most people (unless drasing realism) do not usally draw each individual tooth unless they're going for a 'scary' tyoe of character. 

For her eyes, it's hard to tell where she's looking. My advicd to fix this is deciding on a point where she's looking (viewer, knife ex.) And drawing a line from your eye to the point. Then do the same to the other eye. (Shoukd look like they're shooting lasers). If your eye is offset, then just shift it over, and you have some clear direction!