Willpower depletes—energy management matters more than time management. Identify your peak hours (most are morning or evening), protect them for important work.
Rest: breaks, exercise, sleep. The grind burns out—sustainable pace beats sprinting. Recovery: walk, exercise, hobby time. Environment: what energizes you?
Experiment: track energy versus time for a week. Then schedule important work in high-energy times, admin and low-focus work in low-energy times.