Start keeping a dream journal.
I recommend keeping your dream journal in the bathroom, in easy reaching distance of the toilet. A dream journal is too easy to ignore by the side of your bed. If you wake up groggy, you will stumble out of bed and ignore it. If you keep it in the bathroom near the toilet, you will have roused yourself enough to be capable of jotting down a dream. And you will be in a convenient sitting position. (I am not joking. This really works.)
If you’re wondering why this week’s prompt is to keep a dream journal rather than a specific prompt for a poem/story, just wait. Keeping a regular dream journal can lead to a wealth of wonderful new material, delivered straight from your subconscious.