The first requisite for success is to develop the ability to focus.

My success is due more to my ability to work continuously on one thing without stopping than to any other single quality.

Success is the product of the severest kind of mental and physical application.

The secret of success is focus of purpose.

The reason I've been able to be so financially successful is my focus has never, ever for one minute been money.

The barrier to success is not something which exists in the real world; it is composed purely and simply of doubts about ability.