Exercise and recreation are as necessary as reading. I will rather say more necessary, because health is worth more than learning. Entrepreneurs average 3.8 failures before final success. What sets the successful ones apart is their amazing persistence. Success is going from failure to failure without loss of enthusiasm.
Luck always seems to be against the man who depends on it.
When you get to the end of your rope, tie a knot and hang on. Think wrongly if you please, but in all cases think for yourself. I was always looking outside myself for strength and confidence but it comes from within. It is there all the time. Start by doing what's necessary, then what's possible and suddenly you are doing the impossible.