Go at it like you will your future career. Give it 8 hours of solid work a day and you should do fine. Pace your self, have a game plan for each class and each day and GO TO CLASS EVERYDAY! Get done in four years so that you have less loans to repay. Remember why you are there first and foremost but if you work hard and plan well you should be able to enjoy the experience.
Oh don't forget the study aids and sessions offered by most universities. Ask for help when you need it and form strong study groups that study not party.
I gave my son the same advice three years ago but he didn't listen very well and will go an extra year as a result. He regrets not listening now.
Have a great Christmas break.