Ok! let's start off with postition of the body as compared to the head. It sort of seems you added on the body almost as an afterthought when finished the head- it's of poorer quality and seems "tacked on" to the peice. The circled "black ring" to me is evidence of that. The girl in the portrait lacks a neck and developed shoulders, and as demonstrated by the blue lines, her head is not centered on the body. The torso also has proportion issues- it is considerably smaller than it should be (compared to the head). There are some problems with the striping on the shirt- stripes change width and curve in directions not consistent with how the body underneath would morph them.
Onto the head. Your style is pretty good, you should keep practicing it and developing it further. Since facial proportions in a more cartoonish style are more at the discretion of the artist, i'll leave that stuff as it is. You have a fair sense of where things should be anyways- eyes at midpoint between chin and top of head. (orange)The distance between mouth and chin seems too small- leaves an impression of an overbite. Lower the chin a bit and it should be fine. For the jawline, make sure both sides are symmetrical in a frontal view- on the right side the angle and sweep of the jaw is sharper/higher than on the left.
You draw very good eyes. I have no complaints- they are the best part of your drawing. The highlights in the eyes indicate a light source up and to the right (yellow sun) but these are the only consistent highlights. Keep in mind a light source (or two) where it casts shadows and highlights. The shine in the hair is caused by the light reflecting off of it and towards the viewer. the areas circled in yellow have no reason to "shine". The shadows you put in under the hair strands (in yellow) are isolated- you have no other shadows to go with them. Combine those shadows with the red areas
