Things to learn:
1. Learn to think for yourself. Don't take other's opinions as anything other than that (everyone has an asshole, too. They all stink). [EDIT: Don't mistake the difference between FACT and OPINION when you do this. It is not an opinion that the sky is blue (science has proven this beyond a reasonable doubt), but you can disagree all you want (and that IS an opinion)]
2. Apply logic regularly to EVERY discussion and argument - you won't win friends who don't understand the logic you use, but you may influence people and in the end, that's what really matters. If you don't know how to wisely apply logic, take a Critical Thinking class. Your instructor will show you. If you get mad at the instructor as the course progresses, then chances are, you've not been applying logic properly (I did and I wasn't!).
3. People tell you things for their own good (not yours). Everyone talks to you with a personal purpose in mind, and it isn't always in your best interest. Remember that, parse the words, and APPLY LOGIC and you'll figure out your own way amid all the conflicting information.
4. You cannot and will not please everyone. Trying leads to confusion and frustration. As above, most do not understand the proper application of logic, use opinions and repeat things they've heard instead of do the hard work and learn for themselves. Those who do are seen as "higher than thou" (but isn't that a GOOD thing when you really DO know what you're talking about?).
5. Keep your circle of closest friends small. The smaller the circle, the more you can spend time with and on them and they with you. Having a hundred "acquaintances" doesn't mean your life is any better than it is having 4 close friends. Try to remember that as you go through life - it can make or break you (or keep you from breaking).
6. Surround yourself with people who inspire you - not the people just like yourself. Those who inspire you will make you get better. Those just like you will allow you to wallow in feelings of comfort (and keep you from trying harder).
7. Work hard so that you can afford to play hard. Playing is a benefit of work. Without one, you cannot truly enjoy the other.
8. Learn how to balance your accounts. Save now. Save always. Put money away when you have it for those times when you will not. Celebrating victory early has cost many the battle/game/war.
These are all things that the American school system SHOULD teach, but doesn't. Instead, we have to learn them for ourselves. If by posting these items here, I help ANYONE better themselves, then I will consider my purpose in life fulfilled.