Until I marketed my essay "A Red and Blue Marriage" last year, it had been a long time since I had to write a query letter. I wouldn't mind if I didn't have to write one again! I had forgotten how hard it is to get in what you want to say without sending the editor in a spasm of yawning. How much do you say? Does the editor already know your name, in which case a list of your credits is redundant? If you don't have any credits, how do you convey that you have the necessary gravitas for the editor to ask for your manuscript? Tricky, tricky.
We all really miss the wonderful posts by Miss Snark, who could rip a query apart in just a few words, but who also provided a pretty terrific map for how to proceed. But now, following a link, I stumbled on this wonderful blog by an agent who analyzes query letters. It's cogent and funny, and made me twitch just a little, wondering how often I had made similar mistakes: http://queryshark.blogspot.com/