Tip#1. Don't do it unless you absolutely have to. If you must, put zombies in it.

Tip#2. Do not write while riding a horse.
Ditto a bicycle. Do not write while asleep.

Tip#3. If you can't think of a plot turn, call the vet. Colic is always popular.

Tip#4. Seriously now, if you are stuck with your story, clear your head with deep meditation. It works for me. Whole scenes can float into your empty mind. Good for the blood pressure also.