Make a list of all the tasks you have to complete by the end of the day.
Prioritize this list with alphabet labels (i.e., A is the most important task, B is the second most important task, and so on). Place more importance on tasks that only you are capable of doing. Also identify the 20% of your tasks that take up 80% of your time and be sure to spend the bulk of your time on them.
Work your way down this prioritized list, one task at a time.
Be sure to only focus on one task at a time—multitasking actually decreases productivity and efficiency.