Grit

This Ted Talk is well worth your time.  This seems to me to be about as relevant and true to the key to success as any I've heard.

One of my favorite quotes is along these lines and it's from Calvin Coolidge, of all people

Nothing in this world can take the place of persistence.
Talent will not:  nothing is more common than unsuccessful men with talent.
Genius will not; unrewarded genius is almost a proverb.
Education will not:  the world is full of educated derelicts.
Persistence and determination alone are omnipotent.