Not only does Agent Query have some really useful tips for querying here, the website is also a really great forum for getting others to help you rip your queries apart--I mean, help you fix them so they're way better than what you could've done on your own.
Check out my experience with putting a query letter for Facades on Agent Query here. I was only able to get two responses, but that was because I didn't invest enough in helping other people with their queries. Usually, people will return the favor if you critique their queries. Plus, if you critique people's queries, you're likely to get better at editing your own. At any rate, it's worth a shot, so I definitely recommend checking it out for those of you who are getting ready to query or enter contests such as #Pitmad.
Share your query stories below if you have any! I'd love to hear from you.