In no particular order:

• You are paying for the right to go to the classes....So go and learn. Skipping for the sake of skipping is stupid and a waste of money.
• Really put the effort into your studies. It's why you are there. Those are priority #1,#2,#3 and #4.
  
• Be social and make friends. You will never be in a place where everyone is falling over themselves to make friends with everyone. Take advantage of it.
• When you pick a major, really think about it. It's great to follow your passion and all, but really think about things like career potential, salaries, etc. and decide if the lifestyle you want can be supported by what you decide to study. If not then you either need to A) change majors or B) Readjust you lifestyle expectations.
• Get involved in clubs/activities/sports whatever lets you meet new people. Classes are just one way to meet people and not always the best.
• Since I am assuming you're a guy, really put yourself out there when it comes to girls. College is the absolute best time to learn to handle rejection, figure out what you want in a partner and to just learn how to interact with girls on a different level. High School is like the minor leagues. College and beyond is a whole different ball game.
  
• Get your butt in the gym. You pay for it no matter what so get ripped (or whatever level of fitness you're comfortable with). It will help relieve stress, help with the ladies and help you avoid what's becoming the freshman 25.
• Explore new hobbies. There are clubs for everything you can think of. Give them a try and see what sticks. Never know what you enjoy.
• Learn to say yes to things that get you out of your comfort zone (in a safe way. Not talking about trying to parachute with your bedsheets off the parking garage)
• Don't buy books from the bookstore unless you have too. half.com is a great source for cheaper books. You can torrent them if you want.
• Don't buy logo'd merchandise from the school. Stuff is way cheaper off campus and on the internet a lot of times.
• Don't overload yourself with classes if you can help it. Balance the core classes with bullshit requirement fillers and fun electives to maintain sanity.
• Learn time management. If you do it right you won't be cramming last minute all the time (it will still happen, just not as often), your stress level will be way down and you'll find you have way more time than everyone else. It will feel weird when everyone else is freaking out and you've been finished for a couple days.
• Use all the resources your college offers. Office hours, resume building workshops, counseling (if needed), etc. There are so many resources people fail to utilize simply because they don't know they exist.
• Before you enroll, learn something about finances. Student loans, tuition, meal plans, books, housing, etc. can get complicated. Figure out what you can afford and at what pace you will be taking classes. There is nothing wrong with taking longer to get through college if you're working to reduce the loans you have to take. There is something wrong with stalling adulthood by racking up student loans because you don't want to grow up. Those loans will come back to haunt you.

Most importantly, embrace the experience. College is a unique time in your life that won't be replicated ever again. Study hard, try new things, enjoy the lack of responsibility coupled with significant freedom.