http://qz.com/394713/life-advice-upon-turning-age-30-from-the-president-of-y-combinator/
Short version:
1) Never put your family, friends, or significant other low on your priority list.
2) Life is not a dress rehearsal—this is probably it.
3) How to succeed: pick the right thing to do
4) On work: it’s difficult to do a great job on work you don’t care about.
5) On money: Whether or not money can buy happiness, it can buy freedom, and that’s a big deal.
6) Talk to people more.
7) Don’t waste time.
8) Don’t let yourself get pushed around.
9) Have clear goals for yourself every day, every year, and every decade.
10) However, as valuable as planning is, if a great opportunity comes along you should take it.
11) Go out of your way to be around smart, interesting, ambitious people.
12) Minimize your own cognitive load from distracting things that don’t really matter.
13) Keep your personal burn rate low.
14) Summers are the best.
15) Don’t worry so much.
16) Ask for what you want.
17) If you think you’re going to regret not doing something, you should probably do it.
18) Exercise. Eat well. Sleep.
19) Go out of your way to help people.
20) Youth is a really great thing.
21) Tell your parents you love them more often.
22) This too shall pass.
23) Learn voraciously.
24) Do new things often.
25) Remember how intensely you loved your boyfriend/girlfriend when you were a teenager? Love him/her that intensely now.
26) Don’t screw people and don’t burn bridges.
27) Forgive people.
28) Don’t chase status.
29) Most things are ok in moderation.
30) Existential angst is part of life.
31) Be grateful and keep problems in perspective.
32) Be a doer, not a talker.
33) Given enough time, it is possible to adjust to almost anything, good or bad.
34) Think for a few seconds before you act. Think for a few minutes if you’re angry.
35) Don’t judge other people too quickly.
36) The days are long but the decades are short.