Many things can be said about Courage and many things are decided by courage, however of all things about courage; the following rule is true:

"You gain strength, courage, and confidence by every experience in which you really stop to look fear in the face. You must do the thing which you think you cannot do" - Eleanor Roosevelt

and in the Words of Winston Churchill:

"Courage is going from failure to failure without losing enthusiasm"

Or alternatively as said by George Clooney in the film Three Kings:

In order to get the courage to do something that you're afraid of, you have to do thing you're afraid of.

i.e. If you want the courage to parachute out of a plane, you have to parachute out of a plane in order to get the courage.

It's a crazy way to work but thats how courage works.