Imagine you get into an elevator with a New York literary agent, you have 10 seconds to convince him or her to read your draft. Elevator pitch is your book summed up in 25 words or less. Start doing it now. A good way to do this is to write a pen elevator pitch that will fit on Twitter. If it doesn't fit, tighten your storyline until it does.
Example: Harry Potter is a young wizard who learns that the evil warlock who killed his parents is coming back from the underworld to kill him.
The above example comes in at 25 words and 132 characters and as you can read, it sums up the story.
A pitch, a proposal, a query letter all sort of mean the same thing. Not everyone gets the opportunity to be in an elevator with an agent or publisher. Most writers get their draft ready for submission. A pitch, a proposal, a query, at this stage they are pretty much the same thing.
You don't need to write the perfect pitch, just an interesting one. There are many examples of pitches on agent websites.
Here is a link to one random Google search that provides sample pitch letters of 23 types of books.
Ever heard this reference? This refers to the chest high pile of unsolicited manuscripts publishers and agents receive that block fire exits. Most submissions nowadays are electronic so this slush pile is in cyber space. Usually there is a first person who opens the slush pile of manuscripts maybe a graduate from writing college on work experience, maybe a junior publisher, in some cases it is the receptionist. This is why the hook, the voice, the non existence of typos in the first chapter are extremely important. They read about 5 to 15 pages and make their decision to read more based on that.
It used to be much harder to submit because the slush pile was growing so huge that many publishers simply couldn't justify creating a fire hazard to find that one true gem. But now that we email they can receive so much more.
That's it for now, if there are any terms you'd like explained, please leave a comment and I'll add your query to the next list of terms.