What is the number one productivity hack? Optimize your life for sleep.
For example, the best home or apartment to have is the most quiet one, far away from street noise, anything which wakes you up.
Also invest in some good earplugs, and eye mask for sleeping. And also optimize your bed, blankets, and bedroom temperature for sleep.
Also, no devices of any kind in your bedroom.
Also, don’t consume coffee or caffeine after breakfast. If you’re just tired, take a nap. Instead of trying to force yourself to do more work, it takes more skill to force yourself to nap. For example, when I’m very exhausted, I just lay in my bed, close all my blinds and shades, and put on an eye mask or towel over my eyes, and put in earplugs and I just lie there as long as possible. I only get out or get up, when my body forces me to get up.