Someone posted about this on Absolute Write. It turned out to be so interesting that I couldn't resist doing a double-post today.
This blog post, by Tumblemoose from Tumblemoose Writing Services, is a list of querying offenses that, most likely, afflict every writer at one point or another. At least, some of them do. Sometimes unavoidably--even the best writers can't catch every typo.
Comical, a good read, and overall quite insightful.