Um, well, I'd suggest giving him ((it looks like a he? I'm not quite sure with the anime/manga style, since there are so many effeminate guys)) some chin. As in, uhh, defining it more and making it less pointy. ((Uh, I'm horrible at explaining my critique, haha.))
The only thing I can say about hair is to practice more, and look up references. It looks a bit clumpy right now to me, but that's probably just an opinion of style. The bit in the back that just kind of fluffs out against his neck sticks out though, you might want to smooth it down. That or remove that.. uh, dent that's just above the ear ugh I hope you can understand what I'm trying to say.
Anywho, his nose is crooked and slanted to the right. You might want to fix that and make it more straight. ((But I see is in line with the chin which, at this angle I think should be sticking out more. The chin, that is. Um, if that made sense. Kind of like... not inside the neck and bluh what does that even mean, haha. Sorry.)) Also, his right eye ((our left)) looks a bit squished. I think I know about the angle you're trying to get at here, although I'm not quite sure... did you draw guidelines for this before starting? ((Like mainly a circle and a crosshair and then all of the placements of his features to make sure they're all in place and aligned nicely?))
His arm is too long, you see, when the forearm is folded against the arm completely, the hand touches the shoulder. Here it looks like it could go pretty far back! x) And his clothes have too many folds. They look kind of wet! I think you should remove some, and smoothen down the ones on the shoulders. You should look up references for these too, they always help. ((In fact, reference everything. It helps, trust me.))
There are so many things I want to point out, but I really can't explain them! English definitely isn't my best language, haha. I hope that this helped somewhat though. Keep practicing! -thumbs up-