Alright, so a lot has been said already, but I'd like to put in my two cents and see if I can conglomerate a lot of it into one thing with a bit more.
If there's anyone here who did everything to fuck up their first two semesters, it was definitely me. I hardly did homework, I stayed up all night and slept all day, dated some large number of women, drank some ungodly amount of alcohol, skipped a majority of my classes, wasted away all of my funds in the first half of the first semester on ridiculous things, and a bunch of other stuff. So since I've cleaned up, here's my advice:
As far as friends go, you can either meet the best friends that you'll have the rest of your life or you'll just meet some good friends for a few months. Friends can be amazing in College, but friends can also be extremely temporary. Especially if you're a freshman, people tend to drop out, transfer, go through drama (yeah, you haven't escaped it), or just altogether move to other friends and just stop hanging out with you. Don't get too attached with people, but that doesn't mean to be a recluse and not bother making friends at all. Just have a good time no matter who you're with, try and get together the skill of liking people that you don't like. If you can do that then you'll be able to enjoy what you're doing no matter what it is, and you'll be able to cope with stupid and annoying people which will be an amazing skill once you get a real job or do most anything. Also be able to make friends very easily, if you go with a friend to a party where your friend is the only person there that you know, just talk to people as if you've met them before. By all means be as friendly and open minded with as many people as possible, and get in to as many new things as possible. I started getting into all sorts of stuff like Fencing, Rock Climbing, Cycling, there's so much you can get into that you'll find out is super fun and end up making you much more well rounded. But don't make your entire life about socializing because...
You have to do work. My father told me something very important after I had screwed off in college, "Self Discipline is the ability to make yourself do what you don't want to do." Now sure, that's obvious, I even understood that before he told me that, it's just something you don't really take into account whenever you're not doing something because you don't want to do it. I'm not going to say go to every class, because in college there are indeed classes you don't have to go to. I had two Political Science classes that worked like this: Everything from the tests came from the notes, the teacher put the notes up on his web site and that's pretty much all he went over in class, the syllabus he gave us on the first day told us all the test dates and when all the homework was due as well as what the homework was. If you have a class like that DON'T GO TO IT! Do the homework, show up at the beginning of class and turn it in and leave. Study the notes a day or two before the test several times, take the test. But don't go to class regularly, it'll actually be a waste. Spend that time that you could be spending in class doing homework for other classes or studying. BUT! If you have a class where everything relies on information given during class or that they take attendance in. GO TO THAT CLASS EVERY DAY! I had a technical writing class that I accidentally missed several classes which brought my grade in it down a whole letter, I would've made a B. I also didn't do a lot of the homework for that class, or I would've made an easy enough A. Also, I'm taking summer classes right now, one of them is a history class where the teacher gives lectures and you take notes on those lectures and that's what the test is made up of. We have a test every week and only two classes a week. I missed last thursday to go to a concert, and consequently missed half of all the information on the test this tuesday, I was panicked trying to find notes and nearly didn't get all the information for the test. Also, it's important to do your homework, so many classes I could've done that much better in if I just would've done more of the homework on time.
But above ALL of that, I have one super secret to doing well in college. This is the one true thing that will keep you from doing badly, and will make it so that you have an awesome college experience: Sleep. That's right, sleep. Go to sleep at a good time so that you get enough sleep so that you can wake up in the morning feeling great and not conk in the middle of the day. This will give you enough energy to actually want to go to class, and not feel too tired to do your homework. Don't feel bad about going to sleep early on your friends and missing out on whatever happens at IHOP at 3 in the morning. You will have plenty of time for hanging out, believe me, don't devote all waking and possibly sleeping hours to hanging out, it will ruin you. And sleep at night too! Don't sleep during the day, don't stay up all night doing homework, don't pull all nighters for tests, get plenty of rest at night, and wake up early in the morning to have a full day of full energy. And believe me, I got an award in my dorm for having the worst sleep schedule. I would stay up all night and sleep through most of my classes. Sometimes I would get sort of back on a regular sleeping schedule, then stay up until 4 in the morning or so, then when I woke up the next day I would be too tired to get out of bed and just succumb to sleeping through my class. I would actually have to argue with myself whether it was worth it to wake up just to turn in my homework, even if I could leave right after doing it and go back to sleep or just go ahead and not turn it in and sleep! One time I even ended up accidentally sleeping through a test! If anyone takes any of my advice, be sure to take this one: sleep plenty, sleep regularly.
Of course, you have to realize that none of this will work out, not the sleep, not the going to class, none of it will work out if you don't have the motivation for it. Period. If you don't want to do well in school deep down in your subconscious, you're not going to. If you don't have the drive to go to class and do your homework, then you're not going to do well in school. But if you want to do well, but you just can't seem to make yourself go to your classes and everything, try and find some motivation. Be it your parents, be it a goal (goals are amazing things), be it anything, just have something that gives you a reason to get up in the morning and go to class.
I'd also just like to make a quick note, that an amazing idea whenever you go to college is to start working out if you didn't before. Most colleges have free gyms for students, take advantage of it. Working out makes you feel amazing. If you're nervous to do it because you've never done it before then get some friends to go with you, and don't be afraid to just get in there and start working out on the machines or doing whatever, no one is going to judge you.