In Building Better Plots, Robert Kernen provides a quick quiz to help you decide if your subject matter is strong enough to sustain a novel. I thought these questions were interesting enough to pass along:
Does your concept provide a strong backdrop for exploring the strengths and limitations and psychology of your characters? What specific elements does the plot have that provide vivid comparisons and contrasts that will delineate your character in intriguing ways?
Does your concept provide a strong environment for the messages and themes you want to explore? What metaphors and motifs grown naturally out of that environment will illuminate those themes and messages?
Does your concept provide any realistic hooks that will make it easy for the audience to relate to? What elements will they relate to? Even if you are writing science fiction or fantasy, you will want to give your audience some element to which they can connect their sympathy.
Does your concept provide enough tension to hold the audience’s interest? What are those sources of tension?
The questions seem a bit complicated to help create a story — by the time you’ve answered them all, you’d be sick of the story — but it seems they would be ideal as a tool to help clarify a muddy middle.