Fortunately, these two disciplines-focus and endurance are different from talent, since they can be acquired and sharpened through training. You'll naturally learn both concentration and endurance when you sit down every day at your desk and train yourself to focus on one point. This is a lot like the training of muscles I wrote of a moment ago. You have to continually transmit the object of your focus to your entire body, and make sure it thoroughly assimilates the information necessary for you to write every single day and concentrate on the work at hand. And gradually you'll expand the limits of what you're able to do. Almost imperceptibly you'll make the bar rise. This involves the same process as jogging every day to strengthen your muscles and develop a runner's physique. Add a stimulus and keep it up. And repeat.

— What I Talk About When I Talk About Running by Haruki Murakami (Page 55)