Ever had a nice flow of words going, a story or essay unfolding as if in real time on the computer screen in front of you, and then someone knocks on your door? Or comes in to ask a question? Or rings a phone that you have to answer? Or yells from the other room, "you've gotta see this!"
I'm sure you have, so you know the almost audible pop of inspiration disappearing. You respond to the interruption, do whatever is needed to get back to your work. But suddenly your fingers are like sausages on the keyboard and your thoughts are nothing more than eddies where a moment before they were a rushing stream.
As a teacher who sometimes tries to write during work hours when I don't have students in the office, I've had this experience frequently. On occassion the flow returns to me quickly. More often it takes a while of tapping on the keys with clumsy fingers before I get back into the groove.
These kinds of interruptions are well known to writers, and often there is little we can do about them other than isolating ourselves, hiding out with the phone unplugged. But there is another kind of interruption that we bring on ourselves. We sit down to write and realize that we want a drink. Or a snack. Or we forgot to turn our music on, or off. Or... Well, you get the picture.
Sometimes I get irritated with myself because I seem to find too many little things that I need to do now that I should have done before I began the day's writing. I have a strategy for dealing with this, though. I have a mental checklist that I go through before I actually sit to write. I check to see that I have water on my desk. I check that the TV/stereo is off. I put the book that I'm reading somewhere out of reach behind me where I can't see the cover. I put a pen and notepad close at hand. I close down my email and all websites, except for Google so I can quickly fact check if need be. I tell myself that I'm not allowed to snack before I finish at least a couple of pages.
Of course, I still find ways to distract myself from the hard work of writing, but by arranging my environment ahead of time I at least minimize the interruptions and increase the chances that I'll be able to paddle my writing canoe into mid-stream where the flow is crisp and clear and swift between the shoals.