The Success Begins Today blog suggests working in 48-minute increments with a 12 minute break each hour. Set a timer for 48 minutes. Close out all distractions and work continuously for 48 minutes. When the timer goes off, get up and stretch, get coffee, use the restroom etc, in the following 12 minutes. Repeat as necessary. Don reports that this technique repeated four times a day allowed him to write a 200 page book in just two weeks.
Timer-based work blocks is the only way I get through big projects; however, having just finished writing a book, I can say that even this effective technique won’t help most mere mortals (at least this one) produce 200 pages in two weeks. But over the course of a few months? Absolutely. — Gina Trapani