"Most discussions of the knowledge worker's task start with the advice to plan one's work. This sounds eminently plausible. The only thing wrong with it is that it rarely works. The plans always remain on paper, always remain good intentions. They seldom turn into achievement.
"Effective knowledge workers, in my observation, do not start with their tasks. They start with their time. And they do not start out with planning. They start by finding out where their time actually goes. Then they attempt to manage their time and to cut back unproductive demands on their time."