"Determine what specific goal you want to achieve.  Then dedicate yourself to its attainment with unswerving singleness of purpose, the trenchant zeal of a crusader." -- Paul J. Meyer  

"The weakest living creature, by concentrating his powers on a single object, can accomplish something; whereas the strongest, by dispersing his over many, may fail to accomplish anything." -– Thomas Carlyle  

"A primary reason for business failure is a loss of focus." -– Brian Tracy

"Give whatever you are doing and whoever you are with the gift of attention." -– Jim Rohn  

"Devote uninterrupted chunks of time to the most important people in your life." -– Brian Tracy  

"Our grand business is not to see what lies dimly at a distance, but to do what lies clearly at hand." -- Thomas Carlyle

"When you work, work. When you play, play. Don't mix the two." -– Jim Rohn  

"Single-minded concentration in the direction of your dreams intensifies your desires and increases your self-confidence." -– Brian Tracy  

"When every physical and mental resource is focused, one's power to solve a problem multiplies tremendously." -- Norman Vincent Peale  

"Most people have no idea of the giant capacity we can immediately command when we focus all of our resources on mastering a single area of our lives." -- Anthony Robbins

"It's the constant and determined effort that breaks down all resistance and sweeps away all obstacles." -- Claude M. Bristol

"Concentrate your powers.  Identify what you are particularly good at doing and do more of it."  -– Brian Tracy

"The best advice I ever came across on the subject of concentration is: Wherever you are, be there.  When you work, work.  When you play, play.  Don't mix the two." -– Jim Rohn

"Pay attention. Don't just stagger through the day." -– Jim Rohn  

"Focus and concentration are the keys to high performance." -– Brian Tracy