You cannot control the world, only your reaction to it.
Do not "settle" in a relationship. Go for the best, relentlessly.
Don't assume you have all the answers.
Don't pretend to be an expert, you might get called on the carpet.
Don't lie to get ahead.
Always give compliments. Never withhold praise.
Study and work in a field you enjoy. Money cannot, and never will, buy happiness.
Prevention is worth more than cure.
Everything has consequences.
Alcohol + Driving = epic fail.
Loaded firearms + careless morons = epic fail.
Guns are tools, and potentially an enjoyable hobby. They do not confer manhood, reflect the size of one's testicles, or elevate one to a higher social status. They are not to be misused, or mistaken for leverage in an argument.
Never hit first.
If you get in a fight, try to get out. If you can't, give it 100% in return.
Live within your means.
Save 35% of what you make, always, without exception.
Engage brain before starting tongue.
Etcetera...