I just read a short interview with writer Ksenia Anske. It contains the most brilliant answer on how to "fix" writer's block. The things she describes are the same things that always in the end get me unstuck. So here you have it, the complete solution to the problem with writer's block, in just a paragraph. Putting it here as a note to self for next time.
I don't believe in writer's block. When I'm stuck, I get up and jump around or do a silly dance or stand on my head (for real) and think and think and think. I wait for a new thought to pop in my head, then sit back down and keep writing. If I'm still stuck and slow, it's either because I haven't slept much (then I take a nap) or because the story doesn't excite me anymore. Then I go back and reread it from beginning. That usually gets me going. Or, if still stuck, I read something brilliant. Always gets me unstuck.
The silly dance thing might sound stupid, but it is very potent to do something physical when you want to get out of a bad state, whether it is writer's block or procrastination. Something I do that works is to just crouch down and touch the floor, then jump up and touch the ceiling, then repeat 10 times. Gets the pulse up and gets me into a different, much more creative mood.
Another good tip, maybe as a last resort, is to take a brisk walk or go out for a jog. It's impossible for me to do that without getting creative ideas in my head.