Almost looks like it could be the start of a Frank Cho drawing if you just had a little more experience under your belt-keep at it! I think with the pose she looks like she's covering her own mouth a little too aggressively, like maybe it'd be better if we saw her proverbial "oh!" face as she realizes what's about to happen. I think the hand being there kind of breaks up the silhouette of her face a little too much as well. Where we might see a subtle chubby curve where her cheek would be it's mostly the boniest parts of her face playing off of one of the boniest parts of the body (the hand).
I am not someone that's into this sort of thing but: her feet look pretty good. I think with the foot on our left the heel bone sort of appears like it's being fit into a socket (which it technically is, of course) but it should be overlapping/obscuring that part (the medial malleolus) rather than visibly being inserted into it with. I could be wrong though.
I guess looking into naturally occurring fractals would be a start. I think for a piece like this it's not the end of the world if they're a little "abbreviated" though, it really looks adequate for the prop that it is for the most part.