The important thing is that there should be a space of time, say four hours a day at least, when a professional writer doesn't do anything else but write. He doesn't have to write, and if he doesn't feel like it, he shouldn't try. He can look out of the window or stand on his head or writhe on the floor. But he is not to do any other positive thing, not read, write letters, glance at magazines, or write checks. Write or nothing. It's the same principle as keeping order in a school. If you make the pupils behave, they will learn something just to keep from being bored. I find it works. Two very simple rules, (A) you don't have to write. (B) you can't do anything else. The rest comes of itself.I try to adhere to this rule by taking my laptop to places where the Internet is not: unwireless cafes sometimes, but most often the Metro Bus system. That works for me: it's an uninterrupted (usually) block of time (about 30 minutes, sometimes longer, rarely much longer) where I can't do anything but write.
Naturally, the universe can't leave well enough alone. Friday morning I saw a note: This bus has free wireless. Great. The best way to avoid succumbing to temptation is to put it far, far away. Metro has brought it closer. Lovely.