Pretty good cell-shaded style. Hair looks a little weird though, and I'm talking about the highlights, not the spikes (although those couldn't really ever exist...)
Ear is a little weird though. Even an attached earlobe wouldn't look that grafted to his face. Shoulders are also a bit small.
Anyway that's some things I see that could be improved. Also don't be afraid of shadows.
"If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours."
-Henry David Thoreau, Walden
Thanks for the advice. This was a quick sketch PS'd. I'll try and "detach" ears when I draw them from now on. His shoulders really aren't that small. I focused on the face so maybe I ignored his shoulders.
"Afraid of shadows", what do you mean? His hair? Or the picture in general? This was quick so I probably didn't use enough shadow.
Well, there's a lot more than two tones in real life on skin, so when you're doing finished pieces you could try using 3 shades skin tone, or two shades of shadow depending on where the light source is.
"If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours."
-Henry David Thoreau, Walden