Well, since you asked for us not to go hard on you, I guess my advice would be...Keep practicing.
I recently changed my mind about my futur career, I just might go into conceptual art or manga drawing so maybe I'll be able to give you some pro tips some time soon *wink*
Until then, if you want to go check my own art thread, feel free to ask the link on my profile. The drawings are pencil made and scanned though so I dunno if it'll be of any help to you.
Pretty good sketch, i'm sure if you spent a longer period of time on it it would turn out even better. The pupil in the eye creeped me out a little haha. But yeah its nice.