Questioning your story premises

A post in which WHM tries to take the advice of Kay Kenyon to rigorously question your story premise, but isn’t sure exactly how to do that.

Kay Kenyon recently published an excellent post on her blog titled Eight things I wish a pro had told me. It’s well worth reading. The suggestion that stood out the most to me was number 3:

Rigorously question your story premise. Before you get started on your next project ask whether this one is strong enough. Many books fail for lack of a memorable premise. Is your premise clear to you? Is it too complicated? Questions like these are legitimate and crucial.

I actually grabbed the last four sentences of the paragraph and pasted them at the top of my FICTION-Ideas text file. I have the sense that this is important advice for me. But I must admit that I’m also a bit unsure about what it means. How do I know if a premise is clear to me? What are the signs of that? And especially: how do I know if it’s too complicated? How does that complicated-ness manifest itself?

And what about the reverse? How do you know if a premise is too thin?