1. Stop working overtime and increase your productivity.
A research conducted by the US military showed that "losing one hour of sleep per night for a week will cause a level of cognitive degradation equivalent to a .10 blood alcohol level."
2. Don't say "yes" too often.
In a 2012 study published in the Journal of Consumer Research, researchers split 120 students in 2 groups. One group was trained to use "I can't", while the other was trained to use "I don't". The students who told themselves "I can't eat X" chose to eat the chocolate candy bar 61% of the time. Meanwhile, the students who told themselves "I don't eat X" chose to eat the chocolate candy bars only 36% of the time.
So, instead of saying yes, you can say "I don't".
3. Stop doing everything yourself and start letting people help you
4. Stop being a perfectionist.
The pursuit of perfection may waste your time. Being too detail oriented blinds you to the big picture.
5. Stop doing repetitive tasks and start automating it.
Or, hire some assistant to help you.
6. Stop guessing and start backing up your decisions with data.
Examine all your assumptions.
7. Stop working, and have some idling time.
Sometimes, just walk away from our work once in a while and have some alone time. Alone time is good for the brain and spirit. A certain amount of solitude (but not too much) makes you thoughtful, preventing degeneration into a thoughtless drone.