(I'm not sure where this came from but I like it.)
Return everything you borrow.
Stop blaming other people.
Every day do something nice and try not to get caught.
Listen more; talk less.
Strive for excellence, not perfection.
Be kind to people.
Be even kinder to unkind people.
Take time to be alone.
Don’t criticize anyone for 24 hours.
Don’t sweat the small stuff.
Know when to say something.
Know when to be quiet.
Learn from the past, plan for the future, and live in the present.
Cultivate good manners.
Admit it when you make a mistake.
Understand and accept that life is not always fair.