I snagged this from one of my daily reads, Mrs. Fussypants. Some of mine are the same as hers, but that just shows that great minds think alike (or at least not terribly mediocre minds, in my case!). :)
Live the Golden Rule. Do unto others, and all that jazz.
Remember who's really in control. Here's a hint. It's not you.
Don't believe the hype. Ever.
There is always someone better or worse off than you.
The world owes you nothing. The world was here first.
Attitudes really are contagious.
Do the best you can with what you have.
Teach your children that they are not the center of the universe.
Never speak (or e-mail) out of anger.
Be willing to try (almost) anything.
Don't ask any questions unless you're really prepared to hear the answers.
Know when to say nothing.
And of course, my favorite....