While college is largely about academics, it is also about creating your own social life away from the constraints of your family and your home town. Everyone has a certain amount of emotional baggage, and college provides a fresh start, a chance to make new friends who do not think of you in terms of how you used to be. So while it is commendable to devote your time to your studies, you should not do so to the detriment of making friends and having new experiences. Contrary to popular belief, that does not mean getting completely drunk on a weekly (at minimum) basis with your buddies. There is much more to college life than just alcohol.
Sure, you will meet new people both in your classes and in your dorm. A dorm can be a particularly good place to make friends, though just how much this is true varies wildly depending on the way the dorm is set up and which people happen to be in your hall. If you are lucky, you could end up living right near a bunch of really cool people. But the best way to make new friends is to join some kind of club or organization on campus in which you are interested. If you like to sing, join the college choir or glee club. If you like sports, join intramural teams. If you like popular culture, join the college anime or video game clubs. Depending on the size of your college, there can be a wide variety of clubs and organizations for you to join. The larger the college, the more people should be in each of these clubs as well. That is not to say that if you go to a small college, you will have greater difficulty finding friends in clubs. You may just have a bit less variety.
By joining a club or organization, you will be able to participate in group activities with people that you know share at least some of your interests. And you are far more likely to make friends with people who enjoy doing the same things you do than with people with whom you have nothing in common. Even at small schools there will be such a variety of clubs and groups to join that you should be able to find at least one that you want to join. Once you join, you may feel nervous because you are just a freshman, and the leaders are big, scary upper-classmen who are probably way cooler than you. Well, put those fears aside. They were freshmen once too, and age does not equal coolness. Besides, if they are actually good club leaders, they will be happy to become friends with new blood that likes the same things they do.
Once you join the club, be sure to actually join in the activities. Just because you are a member does not mean that everyone will suddenly like you. You have to show some investment in the club and actually show up so that people can get to know you. That does not mean you have to go to every meeting and every event. Everyone has their own lives, even the club leaders, so it is to be expected that work or what have you will get in the way sometimes. But you will only get as much out of these groups as you put into them. The more time you spend and the more energy you put forth, the more you will get in return.
Some people get so excited about clubs that they end up joining a ton of clubs and find out quickly that they have way too much to do. While it is good if you want to become really active, do not so overschedule yourself that you have no time to sleep or relax. Everything in moderation. For major organizations like a sports team or a music group, you should probably just stick to one, unless there are two that are closely related and coordinate schedules. Clubwise, you can join multiple clubs, but you should stick to the ones about which you are really passionate. Then you can give more to the clubs and get more out of them. Also, every so often, you may run into a bad club run by lazy people. So at the very least, it cannot hurt to join a couple of clubs at the beginning of the year, then trim down which ones you actually attend based on their quality.