Be cool.
Be nice.
Of course, if you don’t know what “cool” or “nice” are exactly, or why you should be cool and nice, you may want to read the Gita:
Jack Hawley - The Bhagavad Gita: a Walkthrough for Westerners
I heard it is one of the core texts of the Hindu religion, and encapsulates the wisdom of all India over thousands of years, so I picked it up. And as long as you filter out the metaphysical mumbo-jumbo (“Atma”, etc.), it really does seem like a recipe for better living.
But in an effort to drill that wisdom into harder-headed readers, the Gita does repeat itself quite a bit. So if you don’t purchase it, meditate on the above two lines. No, seriously, close your eyes and think really hard about them, preferably once a day. You’ll come to many of the same conclusions the book does.