Ever heard the phrase, "Good things come to those who wait?"
Well, it's wrong. Don't wait. Write.
I have recently learned that imagination does not hit if you go through three days of your life ignoring that essay that's screaming at you from its place on your desk. When an essay needs more imagination, don't ignore it.
Write, write, write. It doesn't matter if you're going to cut it out sooner or later. Writing is the source of amazing stuff. When you write, you think. And maybe, just maybe, you'll think of something perfect to resolve that issue you had in your essay.
It works, I swear.