Rule 1: You can never truly "know" anyone entirely. Sooner or later someone you love will do something that disgusts you and someone who disgusts you will do something you love. Everyone has secrets and no one divulges all of them. If someone seems like Marry tapdancing Poppins and is practically perfect in every way, take that as a sign you don't know them well enough yet.
Rule 2: "If you want something done right, you need to do it yourself" is a cliche, but it's a true cliche. And every time you ignore it, you will be painfully reminded of how true it is.
Rule 3: A foolish fighter is a hero. A smart fighter is hero at times and a coward at others. A wise fighter knows which time is which.
Rule 4: If you are assigned a group project, by fate, necromancy, the throwing of chicken bones, and star patterns, you will be teamed up with the biggest useless fuck-ups in the entire class.
Rule 5: Self-interest =/= selfishness
Rule 6: Never trust a man in jean shorts
Rule 7: At any given time, you are, at best, half as smart as you think you are
Rule 8: "Charming" "funny" "smart" and "witty" are not descriptions you get to give yourself. Other people have to give you them based off of their perceptions of you.
Rule 9: You can never know people's perceptions of you and therefore they aren't worth appealing to.
Rule 10: Not everyone likes everyone else. Not everyone is meant to be friends. If you've never had at least one person outwardly and openly hate you, you probably have boring opinions, or worse, none at all.
Rule 69: If you have a problem with the way I do shit, you can suck it.