Stopping interruptions

The book, "Power of Less", had advice that I took once and then forgot about.  I need to go back to it.

The book cites research about how much time the average person loses each time they are interrupted in a task before they can regain their focus.  To avoid this, the book recommends a few things to avoid interruptions.  They are simple suggestions but powerful:

• Pick 2-3 big tasks to focus on per day
• Start the day with quality time addressing the most important task
• Turn on your e-mail and the same one or two times per day to attack your In-box with vigor.  Then shut it down so that it doesn't distract you.
• Turn on "instant messaging" when you need to find people or be accessible, but leave it off most of the day