Below is a list of general guidelines I developed when I was in college. They were designed to keep me a happy and motivated person.
They've been divided into the four categories I feel make up a balanced lifestyle: Spiritual, Emotional, Physical, and Career.
I used to recite them every morning before I started my day. I called them my 'Daily Affirmations'.

Spiritual:

Have a positive impact on other people.
Take time out to relax and focus your powers of concentration.
Always be respectful and polite.
Be spiritual minded, (whatever your religion).

Emotional:
Always maintain a strong PMA, (Positive Mental Attitude).
Always choose the decision that is wisest for your long term future.
Maintain focus on whatever task is at hand.
Do everything to the best of your ability; Work hard, play hard.

Physical:
Always drink a lot of water.
Concerning what you put in your body, always choose the healthiest alternative.
Maintain an active lifestyle.

Career:
Organize your time, structure a routine, and always do things in order of importance.
Don't waste time.
Take time out for recreational activities only when necessary to maintain optimal working productivity.
Do whatever it takes to produce the best product you possibly can.