1. Work like you exercise – in intervals. Glucose is the fuel that powers your brain, and after 60 to 90 minutes of hard work, most of our tanks are running low. (That's why you feel so burned out after a long meeting.) Take a break: Get up, go for a walk, have a snack. Then get back to work.
2. Block out task time. You schedule your meetings and lunches. Treat important tasks the same way by slotting time for them on your calendar. "If you set a specific time for a task, you'll stay focused," says Daniel Markovitz, author of A Factory of One, a primer on improving personal performance.