Go to every class, even if they don't take attendance. Do the readings and homework, even if nobody checks to see that you did the work. Put in a ratio of 2-3 study hours a week for every one credit hour you take (that's why they call it going to school full time).
Use the resources provided to you, including office hours, tutoring, course syllabi, and rubrics.
Join a couple of clubs on campus that don't involve drinking like you want to die, and go to those clubs regularly. You will make friends.
Don't eat like **** just because your parents aren't around. Liquid calories (booze, soda, etc.) account for a huge chunk of the freshman fifteen. Continue to exercise, and build healthy habits early on (you'll thank yourself in your mid-twenties).
Finally, remember why you're there. A lot comes after college and preparing while you're there helps. Do internships/co-ops. Get a part time job. Build your resume and skills so you have somewhere to land when you're done.