Usually what I do is take the subject (or phrase in your case), and write anything you can possibly do with it. Look back, pick up a few good sentences or sub-subjects. Now repeat that with what you know have. Keep doing that until your able to get into a flow of writing and can start to compose your story, poem, ect.
That's how i basically brainstorm ideas I have, that and pacing back and forth through my home seems to spark creativity
