Failure is the key to success; each mistake teaches us something.

I don't know the key to success, but the key to failure is trying to please everybody.

People are the key to success or extraordinary success.

The key to success is action, and the essential in action is perseverance.

One important key to success is self-confidence. An important key to self-confidence is preparation.

Success is not the key to happiness. Happiness is the key to success. If you love what you do, you'll be successful.