Clams, get a job and make as much as you can over the next few months so that you can do nothing but party your first semester at school. This will get your social life on the right track and when your social life is on the right track you exude confidence like crazy. With all that confidence dripping off of you, prof's will see it and round all of your grades up, so it will get your academic career kicked off well too.
This always works.
As for what to do to make money, you ask? I say an internship with Go Powercat would be a good place to start. It would get your foot in the door with the Nucky Thompson(elite HBO reference that you probs don't get since you are only 18 and your parents probs don't let you watch yet due to your age) of Aggieville, will help you score loads of ladies, will get you "IN" with the local bartenders and bar owners, and will line your pockets with fat stacks of cash.