Make your day so predictable that you don’t have to think about what next task you should be doing.
Everyday eat similar food, wear similar clothes, reach the office at the same time and leave the office at the same time, wake up at the fixed time, go to the bed at the fixed time, do the workout every day at the same time, make your day so predictable that you never have to think about what next you would be doing, and then put all your focus and thinking on doing the things that matter.
Take away thinking part from the routine. Boring is effective.