When I read this comment here by louderwords, I said very loudly: "Go outside."
Have some unmediated experience (or at least mediated only by a notebook).
Here's today's writing prompt:
Start walking.
Write down some of your sense perceptions: noise, smell, feel of the air, visuals, colours.
Add an emotion or two.
Add a memory.
Pick up something and throw it.
Whatever.
Write it down. Put the first 17 syllables into a haiku.
Put the rest into something else.
I'm going out now. I'll be back in a few hours with something.
Bye