Frosh, don't be surprised if you end up eating alone the first third of the year. Don't be surprised if it's January and you still haven't found your group. Don't be surprised if you fail your first midterm. Upsetting things will happen -- it isn't until they're over that you might realize how you could've prevented those things from happening.
1. Get out of your room.
To those introverts and ambiverts out there (including me): It's worth the hassle. Whenever I had 15 minutes to spare, I'd curl up on my bed and watch Youtube videos, fold origami, read a book. The introvert in me thrived in those moments. I'm not saying you can't have your alone time -- just don't let that alone time keep you from ever leaving the room other than for meals or classes. Don't let your alone time keep you from connecting with others. Make an effort to get to know your hall, remember people's names, actually learn about your peers (I promise you they're much much less intimidating in person), and build valuable relationships that will likely stay strong for the rest of your life.
2. Attend that first club meeting.
There were a lot of clubs I wanted to join -- I just didn't follow through with them. The first club meeting -- not your name and email from the activities fair -- is what gets you in the door as a real member. Missing that first meeting will make it so much easier to drop the club and forget it ever existed. Clubs not only allow you to gain new experiences and do what you're interested in, but they also build valuable relationships with fellow upperclassmen. It also gives you the opportunity to serve in club leadership positions that year or following ones.
3. Connect with your professors.
Attend office hours, stay after class, email the professor, do anything and everything you must to succeed in the class and also get to know your instructor. Professors are valuable role models, mentors, and resources -- you just have to get to know them. I assure you, they're usually teaching because they not only love the material, but also love their students.
4. Reach out to your peers.
Like I said, don't be surprised if you end up eating alone the first few weeks of freshman year. But that doesn't have to happen -- take initiative and ask your peers out for lunch. Chances are you're not the only one hungry for company.
On an academic note, realize that you can often learn more from your peers than your professor or TA -- while instructors have all the information, your peers are actually struggling like you are. Get together a study group to really understand the material from class and homework.
(And I assure you, your peers really are struggling -- you're not alone. It's easy to assume from lack of complaints and confusion that your classmates are on top of everything. But just as you probably don't brag about how confused you are, they don't either. We're all secretly struggling.)
5. Take Mini-Courses
Those 1-2 unit wonders are the perfect way to learn what you've always wanted to without having to forego other important courses. Begin learning piano, try out yoga, take a nutrition class, learn a new programming language, you name it! Who knows, those mini-courses might actually lead you to passions that in turn lead you to new hobbies, close friends, or even a major or minor.
Doing all of the above from the start of my freshman year would've been nice. While these are things I would've done if I could change my first year, I really wouldn't change the year at all. Struggling academically and personally is a given, and those struggles shaped my freshman experience.
Most importantly, your struggles are going to change you.
Be patient and open yourself to change. This is the perfect time and place for that.