I have a mini post-it on my computer that asks "Have you written today? 5 mins", and has a little picture of a clock.
I write a lot over the course of a normal day: emails, fb posts, homework assignments, discussion board questions, texts, and the millions of constant scribbles on every available surface.* Most of this writing is reactionary; that is, it's in response to someone else's writing. The post-it is really to remind me that I need to write new content, pieces that spur my own action, be that a blog post, a journal entry (it's been almost a year; I have got to update that thing!), or even an email to someone I may have lost contact with. There are so many things on my to-do list that will benefit from daily writing and committing words to paper will serve to spur the Universe to action quicker on all the goals I have.
Writing to fans and friends should be something done on a regular basis, as well. How can you develop the relationship if you don't communicate with them? A short email with insider tidbits on the upcoming production is a perfect balance between taking the time to write it well but not too long before becoming too much information. But these emails can nudge a ticket purchase or serve as a "touch" before the ask. They are just as important as the answer to the boss's question or the planning work and need to be put on the schedule just like those.
*In conversation with a friend recently, the comment was made: "Are you like those crazy people in the movies, when they're finally discovered at home, and all the walls have writing on them?" I laughed. "Not quite that bad," I said, "but almost."