This is simple.
Find your productivity peaks.
The time when you work the best.
This will usually be a 3-6 hour window. So, you may be at your best energy and focus wise from 9am – 1pm and then from 4-6pm. If yes, then plan your most important work around these hours and you’ll get a lot done.
At other times, do work that takes less creativity and energy, like replying to regular emails.
You can also use this time to take a break, go for a walk, take a nap or a shower or to workout.
The key is to sync your important work with your high focus and energy periods and not trying to do anything important when you are not at your sharpest.