(Disclaimer: no one method works for everyone, take what you need and leave the rest, may not know what I'm talking about, etc.)
I've done a two-year stint in a query letter workshop watching people fail to nail down their story. Ask them what their story is about and writers will ramble on about world-building and backstory. Elevator pitches frustrate people for hours. But everyone should be able to express their novel in a single equation:
Protagonist + Goal + Conflict = Story.
It's that simple.
Protagonist: A compelling, unique protagonist. Yes, just one - even if there are multiple PoV characters and multiple plot strands. There is no room for extra characters at this basic a level. Pick the most important.
Goal: An emotional drive, eg. to redeem himself for X, to prove himself to Y, expressed through a specific external goal. For example, the protagonist wants to escape the shadow of his heroic father whom he can never seem to outshine (emotional/internal), so he wants to win the X Award for Awesomeness, which his father never managed (active/external).
Conflict: Something that's stopping the protagonist from achieving his goal. Ideally a person, the antagonist, is opposing the protagonist, unless you're writing man vs nature or something. The more impossible to overcome the conflict seems, the tenser the story. This conflict is not resolved until the climax: if it's resolved beforehand, it's not actually your main conflict. There should be high stakes for if the protagonist fails to achieve his goal, eg. he'll be killed, his family will be humiliated on national television, his girlfriend will leave him, etc.
Everything else is supplementary to the main story. Subplots build up the main plot. Each scene has a scene goal building toward the main goal. Other characters are supporting cast for the main characters. And so on. I think it's the inability to reduce their story to this fundamental level that makes people struggle with queries and pitches.
I've found this equation useful for:
* Story creation. Helps you keep a clear story arc in mind.
* Revisions. If you can nail down your protagonist, you can ensure that s/he is the one with the goal, stakes, conflict etc. If you can nail down your main goal, you can ensure that it stays consistently important throughout the story (bearing in mind that the goal may evolve, eg. as the protagonist discovers that their Mentor is in fact Evil, and therefore their Mission must be Stopped).
* Query-writing. Mix up these elements in a blender with a dash of voice and you're good to go.
* Pitches. Ditto.
Want to get mathematical and identify these basic elements of your story?
