Work hard. Work hard. Work hard.
The hardest part of my two airline jobs so far has been the CPT - Cockpit Procedures Trainer. This was tough both places.
Really know your profiles too.
At my airline an absolute knowledge of limitations and memory items on the checklists goes a long way.
Like the others said, have fun. Work hard, but get to know your classmates. They will be your buddies for the next few months and years. Help them and they will help you.
Get drunk once in a while. Welcome to the airline world!