There are a few things I wish I knew before I started college four years ago.
The first thing is to ignore the advice to "just explore majors" even if the majors you're interested in exploring are difficult and typically result in low gpas. I've found that the encouragement to major in difficult subjects is toxic. Though as a freshman you will have time to raise your gpa throughout undergrad, it still is easier said than done to raise a low gpa. Also, if you start in a major you know you can get good grades in from the get-go, you will have a higher chance of graduating with a high gpa, and also you will not have to deal with the stress.
I think the best advice is to major in what you know you can do well in and you have enough passion for because these factors will motivate you to finish strong. There are anomalies, people who major in difficult majors and finish with a decent gpa, but most just end up switching majors and suffering from a lower gpa as result. So I advise that you're just honest with yourself from day one and major in what you know you can succeed in because grades and scholarships matter.
Something else I wish I knew is that it is best not to depend on your advisors. Some advisors are great and hands-on, especially with freshmen. Others, not so much, and they oftentimes push students in the wrong direction. Speak to professors directly with your concerns or call and visit the registrar's office as soon as you feel like a problem is not addressed rather than depend on your advisor.
Another truth is that the halo effect is real and successful. During the first few days of class, I recommend that you sit in the front and participate. This halo effect will cut you slack later in the semester if you fall behind. Most professors will continue to see you as a hard-working and bright student even if the quality of your work decreases. Plus, the first few weeks of class are often easier than the end when there are finals and papers due.
I wish I knew how important getting along with a roommate is in freshman year. Roommates and room selection are majors causes for anxiety during undergrad. I personally disliked and fought with my first roommate and she eventually moved out. The mistake I made was trying to become close friends with her even though we were very dissimilar and didn't vibe. I suggest being cordial and respectful with your roommate but to avoid going out of your way to befriend them. Only being acquaintances is actually a good thing because it makes it easier to lay down the ground rules and set the tone for your living situation. If you end up becoming best friends with your roommate, great, but if it doesn't happen that's fine too.
Lastly, I wish I knew it was okay to not overextend myself freshmen year. It's actually more than okay to limit yourself to one or two clubs instead of joining them all. There are many years ahead to do more things on campus, it's best to ease your way into things and make your workload heavier as you progress.
What's something you wish you knew before college? Or if you are about to start college, what do you look forward to?