The first step in taking back control is to know exactly what you're up against. Track yourself for a week. For each interruption, note the time and the way it came about (via e-mail, telephone, or drop-by visitor). Include the interruptions you visited on yourself with incessant checking of e-mail, walks to the watercooler, and klatching with friends. Write down how long you spent on each, and grade it: A = critical and urgent; B = important, not urgent; C = unnecessary.
Add up the total minutes spent on A-level interruptions, and divide by five to get your daily average. That's the amount of time each day you must leave open for the inevitable crises that must be handled immediately.
You'll likely have two or three people who can break in anytime (your boss, one or two key colleagues, and perhaps your spouse or child). Postpone dealing with as many of the others as you can. Many issues are important (B level), but, as you'll see from your log, they can wait. The delay has a payoff: It allows you to prepare to respond in a more focused, efficient way.