At Saturday's meeting Kristin talked about perfecting the pitch (specifically in query letters). There's plenty about this on her blog, but to summarize:
Determine your plot catalyst (called the inciting incident in screenplay parlance). This is the event that sets the story in motion and should happen in the first 30 pages.
Shape the paragraph by adding the following:
a) Backstory elements
b) Other relevant plot elements
c) Character elements
d) A combination of the above
Aim for around 6-10 sentences. It should read like a back cover blurb.