Randomly think of a thing. Let it bump around your head a bit. If the bumping gets too loud, start writing the words with the nearest writing device. See how far you get.
When you are close to done, print it out on paper. Sit somewhere else with your favorite pen and edit your work harshly. If this piece is important, let someone else edit harshly.
I liked this. When I was in school, I’d often print out essays and edit them. For the first time in a long time, I did just that.
The technique is supposed to put you in a different space. It allows you to separate yourself from the work and critique it as if it were someone else’s. Try it. My soon to be published review is better because of it.