Nose and cheeks look great! I would suggest studying eyes and brows. They seem to be your major weak points.

Well, I'd suggest consulting Google images or a yearbook or a magazine or something first. Or a mirror! Better to draw from life than to draw from someone else's interpretation of life, you know? Of course, if you get hung up, the gallery is a great place to see how others have done such-and-such on the pixel level, but for a high-level understanding you can't beat real life.

Also, because of the highly stylized look of this and your other face, It's actually hard to say what's a stylistic choice and what's a lack of understanding of facial anatomy. It may be beneficial to try drawing a few faces realistically (and maybe on a larger canvas) to get a handle on what you need to work on. At any rate, I think you've got clashing elements with the nice-looking rounded cheeks and well-drawn nose, and the very angular jaw, chin, and brow.

Sorry if some of this critique doesn't seem very helpful. In my (limited) experience, facial anatomy is just one of those things that you can't grasp without lots of study and LOTS of failed attempts. It's just very difficult to explain concisely how to draw a brow, say, and it's difficult to get anything useful out of edits at this small size without making an almost pixel-for-pixel copy.