Slushpile Hell features examples from bad query letters. Let these examples be a lesson to us all.
There's a fine post at Writer Beware about the importance of self-editing. Frankly I can't imagine not self-editing - I love that part of the process. I rediscover my book, make it better, and occasionally say, "yeah, that's a pretty cool bit."
And for the truly brave and demented, here's an imagining of how Toy Story would have turned out had it been written by Cormac McCarthy. Damn.