Just some fan art

I was thinking of making a series me and my freind were talking and making a script about  for a long time now but, chracter designs is really fricken hard. I already have the main chracter, his friend, and the bus driver down but that is mostly it. Im trying to stray away from the chracters looking to simple but yet convey what the are by just looking at them. I seem to get it right with the bus driver and the main chracter's best friend, but not really the main chracter. I gonna watch some more cartoons to get some more ideas.