But if, and when, you can: Try to avoid multitasking. “It's useful not to confuse multitasking with having multiple commitments, projects or roles to fulfill,” says Marshall.

When she was in high school, JetBlue executive Bonny Simi was asked to note 100 things she wanted to accomplish in life. Instead, Simi jotted down five: go to a good college, work in television ...