If you are stumped by something – stop and daydream. Build in time into your writing time to lean back and close your eyes.
Don’t think. Just let your mind wander. Trust that when you return from your trance, words will surprise you. Daydreaming is a form of trance, allowing flashes of insight come into an empty mind.
Then, after a few minutes, open your eyes and continue to write. Let yourself be surprised by the fresh insights that come to you.
Imagination takes fragments, slivers of dreams and chips of experience, that at first may seem unrelated, and then seek out hidden connections to merge them all into a whole.