I just saw a TV-show with an interview with Swedish writer Jan Guillou.
He mentioned an interesting but perhaps not very surprising technique to avoid writer's block: at the end of the day, stop writing in the middle of the page, maybe even in the middle of a sentence. And the next day you have something to get you started writing again.
That sounds like an author's version of leaving a failing test at the end of the day that I wrote about recently.