Been there too once. Others have mentioned financial things. I will just add a few things. Use credit cards responsibly. Learn how credit works, learn how to buy a house smartly and most importantly, learn how to buy a car properly. Pay cash whenever possible.
Now to the real stuff:
Family, one day them and you will be gone. You can NEVER get that time back. Make amends with any goofy family members. Never know when you will get the call that they are gone. The worst feeling in the world is them leaving this earth and you had a chance to make amends or say you are sorry or love them. TRUST ME on this.
Keep the harmful & drama filled family members at a comfortable distance.
Tell family & friends the truth, even if it hurts. (This does not apply to being married) You MUST always say "yes" & tell the wife she isn't overweight & that looks good.
MIND YOUR OWN BUSINESS!
Know you don't know everything
Shut up and listen
Don't worry what others think
Be the better person and walk away
Work hard at a career, work smart at a job.
When you do find a career, understand CLEARLY that those above you get paid to just be there, not work. One day that may be you up there, so don't ***** about it!!!!!
Look for a career by finding out how many at the top make the income you desire, then work your way to the top!
Ask questions ----> Part of that shut up and listen.
Don't be selfish.
Don't loan something and expect to ever see it again. Money included.
Get a cat or a dog, they will love you no matter how bad your day is.
Find a few fun hobbies
Don't buy a house with a HOA!
Access your self honestly, but don't be too harsh on yourself.
Thank your parents or who ever raised you for all their hard work and dedication to YOU!
Don't believe all you read online, including but not limited to this post!
Make friends with a CPA & Attorney, cause if you follow all of the previous posters & mine you will be successful enough to need them down the road.
Good luck