Working on demensions

First time actually trying to get my drawings to be anything more than 2D. People are round.This guy is my best at representing this.

I used the dude I sit next to in English as a body base (whether he knows it or not HAHAHA) so I was able to check it's being realistic or w/e.

Didn't use his hair though. I'm just (even more) crap at drawing short hair.