My stats are a little strange, because I got an offer on my first full request and had only queried 20 agents in two weeks. For this query, I had:
7 rejections
1 partial request
4 full requests
1 offer
This is the second manuscript I've queried (and I only started it because waiting to hear back on manuscript #1 was making me miserable -- write something new!), and I sent my first ever query in October 2014.
I got a lot of great advice when I posted in Query Help, and I agreed with most of it. But, as you'll see, I didn't wind up really changing the query much...

I was struggling with how exactly to spruce it up and then figured, what the heck, the general response was enthusiastic. I decided content trumped perfection, and I would test it out. So even though I wasn't 100% on it, it worked well enough! But I do want to thank everyone for being so supportive through this entire process. It's made everything much easier.
Dear agent,
All Zoie has ever wanted was to be the main character of a novel. She’s spilled more sweat and aced more tests than anyone else at the character training school. When she graduates top of her class, she’s sure she’ll be assigned a leading role in the next bestseller.
But when her first assignment finally arrives it’s for a bit part in some no-name dystopia. Worse, when Zoie enters the story, she finds out that she and all of the other minor characters are going to die. And not in a blaze of glory taking down an orc king or saving the world. She’ll be just another nameless extra lost along the way to the conclusion.
No character has ever changed a book’s plot before. At least, not successfully. She’s heard the rumors: stories imploding, killing everyone inside, and plots turning perilously unpredictable.
But Zoie figures, there’s a first time for everything. And if she’s going to die, she won’t settle for staying anonymous.
THE WRITER is a 69,000 word YA fantasy novel. Thank you for your time and consideration.
Sincerely,
kaytee