how do you prioritize your tasks as an Executive Assistant?

MY main prioritize helps the executive manger which related me.

Tasks should be prioritized in order of urgency taking into account the estimated amount of time required to complete each task.  Some tasks may be quick and easy however not necessarily the most urgent an vice versa.  

Grouping tasks that can be done simultaneoulsy without room for error is also effective Time Management eg: Scheduling telephonic appointments whilst booking meeting rooms and populating the relevant individuals diaries, instead of doing each task seperately.