Gym sports! I am good at gym sports, I will show you any gym sports you want, but hockey is best one. Gym sports are also good way to deal with bullies: if you are much better at gym sports than them, then they don't bully you. Don't worry about cafeteria food, it is not best but it is fine. For slang, you want Urban Dictionary - just make sure you read whole first page of definitions, so you can match up with context and make sure you have right one.
For study, I used to like taking notes in class, then turning notes into little songs so I remember better. Music makes thoughts stickier.