Q is for query.  That tricky fishhook we writers try to bait with the right stuff to attract the curious eye of those big fish otherwise known as publishers and/or agents.  Your query letter is the first look they have at you—the first time they read your words...about your words.  So while you have their attention you really need to wow them.  Give them something to spark their curiosity so they'll take the next big step.  Like manuscript submissions they get gazillions of them, so it goes without saying that yours need to stand out from the rest. 

Instead of breaking off into a long diatribe about the perfect query letter, here's what you need to do.  Go online and research them.  There are countless examples spread across the digital universe just waiting for you to find.  First learn the format of a query...what's included and in what order.  That much is pretty standard.  Read a bunch of them and very quickly you'll get a feel for the mouth-watering style that makes publishers and agents sit up and take notice.  Think of it as the first door.  If you get through it, bigger and better things await.  There are bigger fish to fry if you catch my drift.