After finishing a book
When I finish a book I have another in the pipeline to work on. Inevitably I'll sit down, excited to start a new narrative and...I'll balk. Like a horse before a jump it doesn't want to take, I'll pull up short. Every time. My brain refuses. It says, "Too many words. I can't produce that many words. I can't." Untrue, obviously, as I just finished a book, but there you have it.
So what do I do? I start working on short stories (less words). It's a good time for me to review the stories I've written and have set aside for edits or wholly abandoned, unsure of their worth. My edit meter is on high, and I'm happy to work on stuff I haven't seen in months or years. In time (usually a month or less) I'll start thinking of the new book, and I'll return to it, no longer daunted by the amount of words.
I don't think I'll always work this way, but, who knows?