The one course that came to me as the greatest revelation would definitely be Organic Chemistry 1. In terms of revelation I mean the realization of how difficult college can be compared to K-12 education. I discovered this class as it was part of my major requirements as a General Biology major. There's really no strategies to having this type of experience because it's bound to happen eventually in your college career because you're paying an absurd amount of money to learn things. In order to learn things, more times than not you're going to have to be challenged. I knew coming into college that it would definitely be harder than before because that's how it always is when you go advance in grades, it gets harder with harder topics that you learn. This jump is next level though, so the one piece of advice I would give to incoming students would be to be prepared to be challenged because it's inevitable, and get your study habits down early. The quicker you get used to facing challenging topics head on and making a "game plan" to tackle them, the easier your life will be.
My greatest success in developing strong relationships with faculty members was joining as many Zoom meetings as I could where I had one on one time with staff or at least where I could talk to them directly and not just watch/listen to their lectures. The greatest obstacle to achieving this were that sometimes the Zoom times would overlap, so I would have to manage my time wisely and choose which Zoom would be most beneficial to me at the time. I would recommend for incoming students to go to your professors' office hours if you have time to as well as to get close with your advisors. Office hours are where you form the relationships with your professors because especially in your classes with 100 or more people, not all your professors will make an effort to meet everyone personally. When you go to office hours, not only will you have extra opportunities to ask clarifying questions, but at the end of the semester, these professors that you've been building a relationship with are more likely to bump up your grade if you are borderline. Also make sure to meet with your advisors whenever you can because their job description is in their title, they are there to advise you on really anything you need. All these faculty members that you form relationships with could also connect you with other faculty for internship or job opportunities.
Forming friendships with new people is one of the best things you could possibly do to make things easier as you get used to life in college. Especially when you make friends with people who take the same classes as you because 1) you could form study groups with them and 2) sometimes its nice to just have people to complain about how hard classes are or how you all don't like a particular professor because these people go through the same exact things that you do, so they will be able to understand you unlike your parents or teachers. You could also join clubs to make friends like that and sometimes the people you meet also take or have taken the classes you are taking, so they can give you tips on how to do well in those classes.
Being that you don't have the same classes everyday, and you're in class way less than what you may be used to in high school with a typical 7:00 AM to 3:00 PM schedule, it may seem like you have a whole bunch of free time, especially if your schedule has a day of the week with only a couple or no classes scheduled. I quickly learned that this time that you're not in class physically is not just free time, and you need it to do all the work you're assigned and to study what you've learned to prepare for exams. Just like I said before, if you are able to manage your time wisely to get all your work done and study a little bit everyday, the less stressed you will give yourself when exam season comes around when everyone else is cramming and super stressed. However, it is also very important to give yourself time to decompress and relax if not everyday, then every few days, because you can only work so hard until you burn yourself out, but when you take breaks and time to relax, you become even more productive than trying to do everything at once.