One of Alfred Hitchcock's well-known methods for developing a story was to come up with a person, an object, information, or a place of great importance to the various characters in the piece. It is this subject—the "McGuffin"—that fuels their various motivations.
Developing a McGiffin of your own is an easy way to come up with story ideas. The item must represent something that at least two different parties are interested in possessing. It could be an object, knowledge, or status. Exactly what your McGuffin is really isn't that important. Who possesses it currently (if anyone) and what characters are willing to do to get it—that's the focus of your story.