It's funny how people think being a professor is a cushy job. There are never enough hours to do course prep, grading, advising, university service, professional association involvement and all the rest. Many scholars I know get their best writing and research done in chunks; summer vacation or winter breaks, weekends, on days when there is no advising, and most of all - Sabbaticals. The Fetzer Scholars provide another example with their regular research meetings and support for each other's work.
For over twenty years, I have reserved Friday mornings from 9-11am as my writing time. I have an accountability partner, Paul Kwiecinski. At the beginning of the time, we do a brief call to share what we are each going to focus on during that writing time. Two hours later we do a brief check-in. It's simple, but it works. I have now written ten books and numerous articles and book chapters with Paul's support, and I think I have mentioned him in the acknowledgments of all ten books!
Jeannel, like Kathryn has said, great question!
Judi