Ooh! Ooh! *raises hand*
Okay, lets see... [now entering criticism mode]
First of all, the mouth in the first pic looks very weird and off-center. Its like, you have a little pile of rather non-anime-like teeth (at least from what I've seen) and they are all bunched on the right side of his face when his head is turned to the left. The nose also seems a bit too far to the side of his face. Also, what is that big black area on the side of his mouth? Might want to fix the tongue too...hmm... Moving right along...
You will probably also want to do the hair a bit differently next time. Firstly, his head seems kindof flat. I'm rather inexperienced and probably need to shut up and let someone experienced do the advice-giving, but part of this impression is given by the 'gap' of hair on the left side. Which shows that his head stops at the top of his bangs. Which is probably not a good thing, considering the other implication that there may be almost no hair in that area (or maybe its just not spiked
).
Well, otherwise it looks pretty good -- the eyes are properly spaced, which is nice. He also has some muscles, which is also good! And on top of that, you're drawing a lot more frequently than I do! Keep up the practice and you could be a really great artist in no time