There's a lot of things I have learned in my first 2 years of college. Coming to college was a wake up call for me. I have changed so much already and you should be prepared!
1. College is way different from high school
If you could breeze through high school easily without studying or working hard (like I was) be prepared to step up your game! I was so used to slacking and succeeding until I began college courses. It took me a semester to realize I needed to change my ways, but after I did I started improving immensely. College is going to be a lot harder than high school and you will have to work harder. You can't avoid homework and you definitely need to reserve several hours of study time a week! The library is your friend!
2. It's okay if you don't know what you want to do yet
Luckily for me I knew what I wanted to do and what I wanted to major in and stuck to it since, but don't feel pressured into picking a major! For your first year or two you can focus on your liberal studies and prerequisite courses! You will not be put behind! There are countless events and advisors who can help you figure out what you want to do!
3. You can choose to skip classes (but it will come at a price)
The nice thing about being independent and going off to college is the freedom to make our own choices. Most professors do not have attendance policies (some do) but skipping too much will put you behind! I have skipped classes and have been fine but some days I skipped I have regretted. There are pop quizzes and there are notes you will miss out on! Also you want to leave your professor with a good impression in case of future recommendation letters and such, so it's good to make sure you're around as much as possible! (Also don't forget you're paying thousands of dollars for each credit!)
4. Socializing is key
Not only is it important to make friends but be sure to make acquaintances with the staff and faculty! The faculty is there to help you, make sure you utilize it! Be friendly to professors and they'll go out of their way to help you! Go to their office hours and get help when you need it, it helps more than anything. They'll use their time to help in anyway they can. A lot of professors will help you through you me journey if you make a good impression!
5. Have fun and party! (Just don't overdo it!)
As a freshman in college I partied every Friday and Saturday (hard). I'm here to tell you it is okay to get drunk and have fun! Don't forget to make some memories while you are in school because that is extremely important too! You're still young and you have to feed your desires and adrenaline! The only thing you have to remember is not to get out of hand! Be responsible! Don't drink and drive, try not to get an underage, prove to your parents you can handle school and fun while being independent!
Extra tips: College "teachers" are not actually teachers, they are professors (a higher level teacher). Also most professors have doctorates so they go by Dr. (Insert name here) not Mr. or Mrs. even if they're not a Dr. just assume they are out of respect. Remember there are people all around you! The dorm walls are paper thin so don't blast music at 1am on a weekday, people are sleeping or studying, have respect! Get as involved as possible! There are so many clubs and events to get involved with where you can meet new people and have amazing experiences!
So learn, have fun, and create your own happiness!