20 Years and a List of Lifes Lessons

So my 20th birthday is approaching (in March). It's a frightening time as I move from having the excuse of "being a teenager", to merging into adulthood.

My younger self and older self transforming into one. Image from chicks57.

Although I don't know everything there is to know in the world just yet, I thought I'd make an update of the list of 20 things I do know... at my ripe old age.

1. Always brush your teeth before you go to bed - your breath will be extra smelly in the morning if you don't.
2. When you get home in the wee hours of the morning after a big night on the town drink at least one litre of water, take an asprin and have something to eat - this will alleviate the worst pains of a morning hangover.
3. It doesn't matter about the number of friends you have - it's best to have one fabulously loyal friend than 5 or 6 that will bitch about you behind your back.
4. Never let peer pressure get the better of you; a girls confidence will jump leaps and bounds after high school if she stands strong and doesn't let anyone tell her how she should be acting.
5. Wait for the right boy.
6. The easiest way to maintain your figure without strenuous exercise? Eat three main meals a day - try not to snack.
   
7. Dump Facebook and jump on Twitter - it's for the socially aware. Facebook's for stalkers.
8. Never underestimate the power of a compliment; give them to everyone you love and be sincere.
9. Bake cakes from scratch - they are miles better than bought ones or packet mixes, you'll feel very accomplished pulling it from the oven.
10. Try to exercise in your everyday clothes. Park further away from the shopping centre entry. Walk to your closest shop for the milk. Walk, walk, walk.
    
11. Every girl should own a vintage bicycle.
12. Find your signature drink; Pinot Noir? Champagne? Vodka and Red Bull? Anything - but make it yours.
13. Stand up for what's right. Don't let bullying happen. Don't let poverty happen. Don't let climate change happen. Don't let facist governments happen. Don't let the free press disappear.
14. Don't be a snob but never be ashamed of your past.
15. Laugh at yourself; seriousness has a place and a purpose but not in day-to-day living.
16. Instead of saying rich, say wealthy. The words we choose have an affect on our attitude towards people/lifestyles/cultures etc.
17. Spend time with the people you love; we all have embarrassing families and some of you may even have daggy friends, but if you love them like I do mine - you wouldn't want it any other way. Always tell them that you love them.
    
18. Reward yourself in any way you enjoy; you're a pretty cool person for being here.
19. Give your memory a break, leave a notepad and pen beside your bed at night it helps if you want to clear your mind of all things you must do the following day... I write a "To Do List" almost every day during the university semester.
20. Travel. Live overseas or away from your hometown for some portion of your life. Nothing will give you as much perspective on life as seeing how other cultures live.

Add to the list; what are some key life lessons you've learned?