Set a timer
Setting aside time for particular tasks will help you concentrate on one thing at a time and minimize the risk of external distractions. Because you are aware of the time limits, setting time limits can also help you focus your energy on the work at hand.
Make a time period on your calendar to complete your to-do list, and stick to it. Timeboxing has the benefits for you such as making sure you complete tasks, signaling to others when a meeting time is convenient for you and separating work from home life. Or you can try using a timer to work for 25 minutes, then take a 5-minute break. This way, you can focus fully on a task for the allotted time and do something else in the breaks. Using time-control apps to set a phone-free goal is another good option.