Thomas Edison

I never did anything worth doing by accident, nor did any of my inventions come indirectly through accident, except the phonograph. No, when I have, fully decided that a result is worth getting, I go about it, and make trial after trial, until it comes.

Genius is one percent inspiration, ninety-nine percent perspiration.

Opportunity is missed by most people because it is dressed in overalls and looks like work.

Our greatest weakness lies in giving up. The most certain way to succeed is always to try just one more time.