If the Pomodoro Technique doesn't work for you and you prefer to do tasks from start to finish in one sitting, you should adjust your plan to fit with your focus.

So work until you complete those tasks, and then take a break.

Start with the small tasks, the ones you can finish in 10 minutes and run through them first.

You’ll feel motivated by the win of knocking out a couple of tasks quickly and ready to handle more serious work.

Instead of reacting to things as soon as they show up, write them down and then later do a bunch at the same time. 

This prevents them from constantly interrupting your workflow, while still making sure everything gets done.

Schedule your most important tasks for the time of the day that suits you best.

It doesn't matter if you're not the most productive in the morning. Just find your golden hours and do your most important work then.