During my self-help bingeing years, I probably consumed two dozen books that tried to tell me how to manage time. Very little of that wisdom stuck. The real help came from the authors who talked more about goals and priorities than time-management. Folks like Steven Covey, and Dan Sullivan of The Strategic Coach. But once you set goals for yourself, how do you actually get there?
The best system I have found is 'The Three Things'. I don't know where it originates, but at least once a year I read an article that promotes the idea.