It can be easy for one to simply pawn off school as a time to work little, and play a lot. I for one, was one of these people. High school felt like something that wouldn't matter much to me in the long run, as college was what employers really cared about. Cue senior year, at which point I had a decent GPA, but absolutely no extra curricular activities to put on my college applications. Luckily I still managed to get into my school of choice due to a program for first generation college students.
With High school in the rear view it can be easy to get caught up in the college lifestyle. Many have the misconception that, "No attendance policy= no attendance needed". Again, I was one of those people. I quickly realized many Freshman classes had little to no homework and no attendance policy, which led to me skipping a lot more than one should. Whether or not homework is assigned in class, or attendance is taken, you should still go to class and enjoy it, otherwise, what are you paying for? Also, the student who goes to every class session, is the student who passes every class.
I managed to break this bad habit by Sophomore year but quickly picked up another bad habit: not reading for class. Just like every other bad habit, it is extremely easy to skim over your reading or toss it aside. It's true that many professors won't test you over EVERY page of reading assigned, however, it can never hurt you to do the reading, as it will give you a greater appreciation of the class as a whole. This will also give you the knowledge and confidence to speak up more in class, which can lead to a great relationship with your professor, as well as other students. Networking is extremely important for post-college life, so meet everyone you can during your stay at school.
Lastly, enjoy yourself. Parties, drinking, and spending time with friends, are all part of college. That said, save those things for the right time. In my five years at college I never once had a teacher schedule our classes for a spontaneous Saturday session, and I can guarantee you that yours won't either. The weekend is exactly that, the week's end. Work hard, enjoy your classes, and earn those Friday nights of heavy drinking and shenanigans, as they will be all the sweeter when you worked for them.
In summary, you only get to be a young college student once, don't take it for granted. You have your entire life to work and play, so make some friends in class, form study groups, and learn something!