Make sure you're not too 'goth' though. The difference is subtle, but still pretty obvious.
You'll need a greyish black denim jacket, worn over a tucked in black shirt. Spiky belt, with greyish black pants. Don't forget the black nail polish, either. And rings/necklace. Why do I know?
Cuz this guy is plastered all over my school yearbook (went to Mt. Carmel):

EDIT:
I know the jacket's leather but denim works better because you can fray the elbows and write terrible lyrics in lipstick and shit all over it.