Establish times when distractions are acceptable
Educate your environment as to when it is best to get with you by phone or in person for activities that are not urgent and critical.

Put your “big rocks” in first
Make a list of all your current important projects that are not urgent.  They could be reading a book, creating a new marketing letter, creating a list of all the industry sites in your market, etc.  Now assign at least two one-hour slots a week to do them.  Keep these appointments with yourself the same way that you would with a client.  DO NOT allow yourself to schedule anything during those times unless it is a TRUE emergency.  If you do not begin to do some of the strategic work now, when will you?

Minimize multi-tasking
Practice being fully present and engage in one activity at a time.  If someone pops into your office while you are typing an email, ask them to send you an email to schedule a mutually convenient time to get together.  What makes typing an email, writing a letter or even just thinking activities that can so easily be interrupted?  Would you begin talking to someone if they were on the phone talking with someone else?  I doubt it!  So, why do those other activities not require the same level of focus? I doubt a doctor is checking emails or taking phone calls in the middle of surgery. I suspect a lawyer is not constantly checking his Blackberry while the opposing counsel is grilling his client.