Two from  the late, great, Coach John Wooden (perhaps shortly after my death people will be quoting me as the late, not so bad, Andy Berkowitz):

Failing to prepare is preparing to fail
— Coach John Wooden
Ability may get you to the top, but it takes character to keep you there
— Coach John Wooden
those of us that are blessed will be able to learn from his brilliance and his flaws— The will to win is important, but the will to prepare is vital.
— Coach Joe Paterno

Both of these men will always have the word "Coach" proceeding their name, and it should rightly be capitalized

Adversity causes some men to break; others to break records
— William A. Ward
I say to my struggling addicts :You can’t get to the mountaintop if you haven’t been to the valley
— Dr. Andrew Berkowitz
I always try to turn every disaster into an opportunity
— John D. Rockefeller