These are the kinds of activities that we should concentrate on minimizing. Humans tend to let QuadrantThree activities dominate their time, when they should be concentrating on QuadrantOne and QuadrantTwo activities. So, find ways to clear out the QuadrantThree activities.
Suggestions for minimizing QuadrantThree activities:
Practice politely rebuking people who are interrupting you
Find some way to mark yourself busy, to minimize interruptions
If you're working on something truly important, don't answer the phone or check your mail (you can always check them after you're done with whatever you're doing)
Only check e-mail a couple of times per day, at specific times.
Keep a list of truly important activities highly visible in your work area, so you can refer to it frequently