Turn the Bell Off!
This is a trap that I have found myself completely caught in. I am working on a project on my computer and all of a sudden I hear the familiar "dah duh, dah duh" of my email box announcing that I've got mail. Curious, I stop what I am doing and checkout what has just arrived. Or even worse, a little window pops up with, "Message from Wendy". I wonder, "What does Wendy have to say?". Fifteen minutes later I am finished responding to Wendy and a few other messages that have arrived. I am now totally derailed from what I have been doing on my project.
Email is a wonderful tool but it also can be a MAJOR interrupter and time waster. Try turning the bell and popup off. If email is critical to what you do at work, schedule a consistent time (like the top of the hour) to check email. Otherwise, fight the urge to check email too often-maybe only check it 2-3 times a day. You will be surprised how your focus will increase as well as your productivity.