A high percentage of top performers keeps some form of daily performance journal. Tennis champion Serena Williams and former World Series MVP Curt Schilling use notebooks; the rapper Eminem and the choreographer Twyla Tharp use shoeboxes, which they fill with ideas written on scrap paper. What matters is not the precise form. What matters is that you write stuff down and reflect on it. Results from today. Ideas for tomorrow. Goals for next week . A notebook works like a map: It creates clarity.