If you finish a day feeling you’ve accomplished nothing – with a job which has lots of activities initiated and controlled by yourself – then you have a problem of mastery. Improve your planning and your methods (use of Outlook being a method).
If you finish a day feeling you’ve accomplished nothing, with a job which has lots of activities initiated and controlled by others, then you have a problem of influence. Improve your relations and your assertiveness .
In both cases the problem is within yourself. Answer the following questions: Who sends me emails? When? Why? When do I answer? Why at that time? How? What precedents have I created?
