What's your major? That is actually significant for getting good advice.
Balance fun with your studies. If you're feeling just a little behind, yet are tired from working so hard, but are still going to some, but not all, social events, then you've probably got it about right.
It's also easy coming out of high school to think your class schedule looks a lot more sparse than it really is. You may not have as many hours scheduled for class as you think you should, but all those hours are open because they fill up later. They really fill up.
If a class regularly has optional homework, do it or drop the class. I thought I had a handle on this one subject and didn't bother with the optional homework because it all seemed so easy in class. Thought I did poorer than expected on the first exam, figured I still got at least 85% though. The exam came back with a big red 49% at the top. Do the homework or drop the class.
Take a geology class for your general science if one is offered; they usually have field trips. Often, these are weekend camping trips. You camp in national parks over the weekend and get credits for it. There are also usually stand-alone trips offered through the term that are a day to a weekend long, also for credit. Plus geology is a pretty cool science, especially if you're into Minecraft or Dwarf Fortress.
Do not stay in your dorm all the time. Play games alone only when you have 30 spare minutes or so and nothing better to do with it. Free time is much better invested outside your dorm. Hang out with or meet new friends, go to the recreation center (you've already paid to be a member with your student fees, so use it! Swim, play sports, rock climb, work out, whatever, just don't waste it). You can game just as easily when you're out of college.
Do not assume that people will handle your paperwork correctly. Double-check the administrators on everything that pertains to you; I've been mistakenly dropped from classes without being told and had my major changed from geology to biology on my graduation form. Assume that no one in the administrative building is capable of doing their job, but don't be a jerk about it, just check their work.
Make friends with the secretary of your department; when bad things happen, they are your best chance of fixing it, even if it means going slightly outside the regular procedure. They will cut through red tape and make shit happen for you. Piss them off at your own peril.
Don't brown-nose, but show your adviser or the profs you work most with that you are reliable and do good work. You'll be asking them for letters of recommendation later.
Learn email etiquette if you don't already know it.
Don't browse porn on lab computers. Assume everyone else does and treat them as the keylogging password collectors they likely are, especially in dorm computer labs or other high-use areas.
Try to have an exit strategy if you can. Very few do, and most make it afterward, but having a post-graduation plan will give you a lot of peace of mind during your last terms.
Are you planning on grad school? If so, grades are important but not absolutely essential; you can get by with a couple Cs provided you have good explanations for them. More important are your letters of recommendation and the stuff you do besides classes that shows that you're talented, hardworking, or passionate. If your professor has a position for an undergraduate research assistant, apply for it. Join clubs, participate in community outreach, and anything else that says "This is what I want to do and I'm good at it." But only do that if you really do want to do it; if you're apathetic towards your major, then it may not be for you. This is also a good idea even if you're not planning on grad school. Everybody's got degrees these days so they're more of a minimum requirement now. Employers will look for what you did besides get your degree.
If you are concerned that your major might not be for you, do not hesitate to explore other options. The first two years are your opportunity to experiment; spend your electives in what sound like interesting subjects until you find one that really grabs you, and don't be afraid to change your major if you're passionate about this new thing. In addition, even if you don't change your major, pursuing electives in a side subject you like can be beneficial later on. It gave me a career and got me into grad school, and could, possibly, get me into my dream job.
That's probably enough.
Oh, and have a crap-ton of fun.