12 Rules to Live By - Robert Louis Stevenson - I found this list on another blog and it really seems like a perfect list. If you can do all these things you will be happy.
Make up your mind to be happy. Learn to find pleasure in simple things.
Make the best of circumstances. No one has everything and everyone has something of sorrow.
Don’t take yourself too seriously.
Don’t let criticism worry you. You can’t please everybody.
Don’t let your neighbors set your standards; be yourself.
Do things you enjoy doing but stay out of debt.
Don’t borrow trouble. Imaginary things are harder to bear than actual ones.
Since hate poisons the soul, do not cherish enmities and grudges. Avoid people who make you unhappy.
Have many interests. If you can’t travel, read about places.
Don’t hold post-mortems or spend time brooding over sorrows and mistakes.
Do what you can for those less fortunate than yourself.
Keep busy at something. A very busy person never has time to be unhappy.