My definition of success is "the fulfillment of your soul's purpose."
Don't waste your life believing you can't.
Everything you want is on the other side of fear.
When you think you can't, revisit a previous triumph.
What is the why behind everything you do?
I like Dr. Daniel Amen's 18/40/60 Rule: When you're 18, you worry about what everybody is thinking of you; when you're 40, you don't give a darn what anybody thinks of you; when you're 60, you realize nobody's been thinking about you at all.