My past experience in entrepreneurship and as a business analyst in a Fintech start up taught me to make as little decision in life as possible. I get into the same routine, make as little decision as I can. I use the time to think about business solutions for my current businesses.
The best tip I have read is to remove all distractions for a short period of time as you work. Nothing is too urgent. Know that you cannot multi-task. No one can. Switching between tasks is wastes your time and attention.
Use your brain for processing information. Do not remember tasks. Don't put information and details in your memory as much as possible. Automate as many things as you can. I prefer to use project management tools like Asana and Wrike to put a record of my tasks for the week.
One hour of focused work is more productive than 3 hours of interrupted work. Put on headphones to work. Yes, people might think you are rude, but you get to achieve a lot more when you are uninterrupted.