1. Be kind to yourself. Forgive yourself. Try to love yourself in the good way. Try not to love yourself in the bad/destructive ways. The less you are kind to yourself, the more you will try love yourself in the bad/destructive ways. You are going to mess up/fail, you are human. Be kind when you do.
2. Don't go to court in your head about others (especially your partner). Deal with issues in the real world. Really try to not get to in your head about anything. But definitely don't go to court in your head. Tangential: The tally won't always come out in your favor. Figure out how to not resent that. Especially as you get to points like 'the honeymoon hangover', the seven year itch, that 10-15 year place that can feel so indifferent, roommate like. If they routinely f up on doing the dishes, but are good everywhere else, you WON THE F'ing lottery, so don't get hung up on the friggen dishes. Your going to do them, and it's actually ok and not a big deal.
3. If you have to tell yourself you deserve it/it's just a treat/just an escape/whatever, leave 'it' be/behind!
4. Take extra care of your teeth.
5. Skin cancer is real and 40-50 year old you is going to still want to live and have all their body parts (such as a nose/ears) and minimal facial scars.
6. Money isn't everything, but having enough prevents a LOT (majority) of problems/stresses those that don't have it have. If you choose money, you can choose something else later. If you don't choose money you are most likely hit for the rest of the ride and are picking hard mode.
7. If you are going to play the game, play the game. If you aren't, figure something else out because again you are choosing life on hard mode. We are a society of monkeys. Life is way easier if you play the game. Don't chose 'not to play' because of others or because others you know aren't playing, especially if you run in a crowd of people who 'don't play the game'. They unlike you might have fallbacks, or might just not give a shit if they ruin their lives, or if it's a partner just have unrealistic expectations that you can somehow magically live as if 'you played the game' later on (you most likely can't). If you partner doesn't want to play the game in their 20-30, they are most likely going to want to play from 40 on, and if you can't somehow win at that point they are going to blame you. It's way easier to play the game, even if you have to tell yourself you are playing it ironically or some meta shit.
8. There's a reason why everyone says it, kids grow up really really quick. When you are in it, it seems overwhelming and like you have been forever with the stresses, but it goes really really quick. There will be a last time you read them a book goodnight. A last time you tuck them in. A last time you pick them up. A final hug. A final goodbye. You are going to leave them all alone in a fucked up world world in the end, try to do right by them while you can. Plus the memories they give you are going to sustain you through your life so make them good ones (remember that good memories for a kid could be that one time you make weird 1960s jello together, something that costs $1 and is that simple just might be a lifetime memory for them. For me there used to be stuffed croissant place in Capitola. We couldn't really afford them, but my mom knew when to get there to get day old ones half price. I felt like we were royalty when we ate a day old chocolate or ham and cheese croissant, in fact it was way more special than the extravagant meals we later ate when she had money).
9. As I get older and slowly turn invisible I've learned life is way different when you are attractive. Get as fit as you can. Groom yourself well. Wear clothes that fit. Get a haircut picked to flatter your face. Also a flattering haircut > a trendy one (unless you are amazingly attractive. An attractive woman can pull of being bald, but most of us especially men can benefit from a little help). If you are male and are playing the game, a nice watch is worth it. If you have no budget get something used and classic that will last. I have many life changing interactions where having really nice shoes/a nice watch made a difference. It's horrific and shallow and just the way the world works. If you are going to play the game, play the freaking game. Don't get 'trendy'. Like the haircut, get classic nice. Unless you have money to constantly replace 'trendy'.
10. Don't lie. You will get trapped telling more and more. It will come back on you. Just don't lie.
11. Find things to look forward to. It can be life events, vacations, a nice meal on Friday, whatever, but you NEED things to look forward to. Even now when I have nothing, I hype to myself shows/books coming out to look forward to.
12. The dead parents club is a thing. If you had a relationship with them you never get over your parents dying.
13. At some point, unless you die young, will be disabled in some way. Appreciate/exploit the health you currently have. Take advantage of it. It will go away. Have compassion for people who aren't so lucky.
14. Ignore the 'I'd rather enjoy life than live forever' bullshit. My dad preached that. And he's still alive. But my mom, whom he influenced? She died way way to early, very very painfully from cancer. Live life, but see point 3. If you are justifying then maybe slow down/cut it out/pull back a bit. But do live. I bought a boat when my kids were little. On credit. Because if I waited until it financially made sense, my kids would have already have moved half way across the world. But I KNEW it was insanely stupid and came at a pretty big cost. But the reward was worth it on a much higher level (to me) than 'i'm going to smoke, drink, and eat steaks every day'.
15. Be kind. Be especially kind to those that have a hard go of it.
16. If find yourself buying lottery tickets/getting road rage, you need to figure out what you need to adjust/change in your life.