Agree with what others said about saving, credit, and staying in shape. Another thing to add is to not fall into peer pressure. The decisions you make won't have the same consequences as when you were younger. Don't think because someone is your friend now that they'll be in the future or that they have the best interest in you. People change all the time. Don't waste time on people that aren't gonna do anything for you. I've stopped hanging with plenty of friends cuz it was either not beneficial or they were doing things that I felt wasn't contributing anything positive to my life. If you feel that someone is constantly doing actions that you find questionable or is not worth it, then start to distance yourself from them. Cuz if not they'll start to slowly bring you down with them or expect you to lift them up. I've made the mistake of lending friends money and never getting it back. The money wasn't important but the principle is. The same people you know in high school may not always be the ones you hang out with in your 30s. New people are met all the time. Don't linger around too much with people who aren't worth it. Not everybody is on the same path as you. Focus on yourself first. Another one is to treat everyone with respect. You never know who's fighting what battles or what others may be going thru. It's a small world and you never know who you're going to need one day.

If anything, buy a house you won't even live in, rent it out.