A lot of times people ask me, "Kujo, how come you so happy all the time?" (Disclaimer: no one ever really asks me this) I actually only have a few simple rules for life that keep me rooted.
1. Don't be so serious. I am always amused when I see people running around texting, talking, twittering, and various other t's that apparently require their immediate and urgent attention. People take so many things seriously that really shouldn't be. I've never seen any proof that life is meant to be taken seriously, and until I do, I'm just going to lie back and chill.
2. Do the things you like. If you don't like what you're doing, ask yourself why you're doing it. If you don't know why you're doing it, then stop. If you don't like why you're doing it, then you need to reevaluate your life decisions. If you're doing it in pursuit of a greater goal that you do like, then keep that goal in mind and focus on that.
3. Smile! It only takes a single candle to fight back the darkness.
4. Pick your relationships wisely. You don't want to be around people that are causing you unhappiness or holding you back. Special corollary for those special someones who have dumped or rejected you (since I have much experience with that): When you've been dumped, the best revenge is to live life to your fullest. Become the best person you could possibly be. Do the things you've only dreamed of doing. Make her regret it, not you.
5. Spoiler alert: You're going to die someday. Morbid? Yes, but until you realize that fact you risk wasting your life on things that you don't care about. Life is not a race! You don't want to get to the end, look back and say "Well, that was a waste of time." No one's keeping score, so lighten up and enjoy the ride. :)