Our mind can only focus properly when is given one task at a time. Handling too many tasks simultaneously decreases the attention spans and obliges us to refocus each time we return to an already begun work.
The path to above average productivity is paved with focusing on single objectives at a time with maximum work performance. If you happen to be threatened by boredom, a short break should be taken. While relaxing reaffirm your initial motives for completing the task and how it will improve your life/experience. If you want to improve your mind performance then you can explore https://www.thebusinessbrain.co.uk/.
Before getting busy finalizing the task at hand, be sure that's the most important one on your current schedule. Many fool themselves that being occupied means being productive.
Oftentimes one task is all that you need to take care of in order to clear a truckload of paper work or insignificant but stressful things on your desk.
So don't invest time in little projects that can be taken care of by your employers or collaborators. Focus only on those that deliver the highest paybacks. Consider putting into your payroll some freelancer that would finish less important task for little money then you evaluate your own time.