1 - Don't take life too seriously. Go out and have fun and do what YOU want. Live to make yourself happy (as long as you don't hurt anybody in doing so). Sometimes, it is okay to let loose and forget about the world and have fun with your friends.
2 - No matter how much you want to, don't give up. If I would have gave in and gave up in my first few years, which at points I desperately wanted to do, I would have never grown up. You have to work through the hard times, and even though they are hard - you WILL get through it and you WILL be a better person because of it. You will learn something new and wonderful about yourself, and you will find strength in yourself that you didn't even know existed.
3 - It is okay to change your mind. You don't need to have a single direction, if you are in one program and do not like it - it is EASY to change. Maybe you will have to stay back one extra semester, but in the scheme of life - that isn't bad at all.
5 - If you need help, ASK! It doesn't even have to be a teacher, it could be a peer. Guaranteed you are not alone in this, and asking for help does not show weakness. It is super helpful and can even help you build friendships.
6 - Even if it is something small, it is always good to hold a goal in mind. That way, you never really lose motivation. You always feel inspired and like you are working in SOME WAY to better yourself or your life.
7 - It gets better. It always gets better. You could be in the darkest place, and then, all of a sudden, the light will begin to shine through. It may take time, but it WILL happen.
8 - You are your own problem. But you are also your solution. Remember that. You cannot blame failures on anything outside of yourself, but you should also know that you cannot attribute successes outside of yourself. Hard work pays off.
9 - Being in a relationship should not be your goal. Everyone wants a boyfriend, but most boys at this age are not mature enough mentally to handle a relationship - and you could end up getting really hurt. This does not mean don't date. Date the crap our of people. Just really be careful before giving them your heart. Trust me on this.
10 - Remember, the friends you meet in university are the friends you will have for the rest of your life. So go out, and meet people. Keep your old friends, of course, but don't let them stop you from making new friends.
that's all for now, folks!