Since I ALWAYS have several projects going on at once, I tend to divide my time by days. For example, today is designated as “revisions to really old manuscript” day. I’ll also do some errands, of course, and email stuff — by the time all of that is done, I will be lucky to get a solid 2 or 3 hours of work on the revisions. Summer schedule, of course. Tomorrow I go backpacking for the 4th of July, so I’ll excuse myself from writing chores, but Thursday is “write letter for outside reviewers” day. Plus a dentist appointment.
I also have issues with getting started writing, but what I tend to do is to break down the job into little segments. For example, I’ll start by outlining the whole piece that I want to write, and then I can get myself started by choosing a piece of the outline and writing it. For me, the problem is often feeling overwhelmed by the huge thing I have to create. If I can nibble off pieces instead, I cana feel successful by just doing a little part of it.