This is a nice character, although she could use some trousers. Here is what I see:
Lack of construction. The figure is rather flat, rather than built from 3d forms. No light source is defined, some shadows contradict each other.
Face and hairThis is ... not good. The back of the hair/braid/thing lines up vertical, but the head is tilted to the side. The large chunk of hair in the front does not appear to attached to a skull - no sense of construction here. The chunk also covers the eyebrows, which some hairstyles do, but eyebrows are useful to help convey expression.
The strands of hair in the front must be stapled to her face because they ignore gravity. But if you move them out of the way, the problems with the face emerge. Eyes are very wide, which implies a wide face, but the ears are stuck on right next to the eyes. The nose ... isn't really a nose, and the mouth is tiny.
The lines of the jaw are asymmetric, which would suggest the head is turned slightly (in addition to being tilted) but the features are mostly centered. It's a tough angle to try and pixel at, so you could probably get away with it once you fix the structural problems.
TorsoMostly ok. I don't get the placement of the wrinkles. It looks like they were placed just to break up the space rather than define the form. The ones in the center of the chest make it hard to see the heart symbol.
Arms, thighsHands are a little small, I think. Arms might be a little short too. I don't know where the shadows on the arms are coming from (particularly the shoulder on our right). The legs are flat, but I assume this is just unfinished.
ColorsI think you could spread the values more. A few dark colors to balance out the mid and light tones.
An edit. Some things are working, some things are not (goofed up the purple colors), some things are experimental (both warm and cold shadows). I used a reference for the t-shirt, for the placement and drape of the folds.

Tourist