Soft Skills: The software developer's life manual — Productivity section
1. The reason the Pomodoro Technique works is that it quantifies your working time, allowing you to see how many Pomodoro intervals you can complete in a week.
Note, having 8 hours in a day does not mean you can complete 16 Pomodoros — this is perfectly normal.
2. Establish some routines, for example running three laps every Monday, Wednesday, and Friday. Do not schedule tasks far beyond your capability; if increasing the workload makes it so difficult you cannot maintain it long-term, still stick with it for one week and then reduce the workload, otherwise you will lose respect for the routine.