Since a child, my eyes close early at night. I get up early in the morning, because that's when I'm freshest, and have more energy to think and do things. By the afternoon I'm all worked out and do less energetic things. I move from one activity to another so I keep my concentration fresh. That's how I achieve my goals.
That's what you call energy control and scheduling. Working according to your personal energy.
You see, interacting with your tasks, makes you feel more alert. Than if you hog, push and force yourself to finish a big boring task, your brain switches off and you are all pooped out!