Orignally posted August 3, 2010:
Here's a great list of mistakes that could land your queries or submissions in File 13. Some good advice here:
Some agents and publishers are fuss-budgets, so it never hurts to make your query slick and professional.
It may seem tedious to have to write and rewrite a query letter, but it's time worth investing. The whole point is to make the agent/publisher want to read your manuscript. If they're distracted by misspelled names, irrelevant information, bad grammar, etc., they're not going to want to invest the time it would take to read your work. The same way too much backstory, bad grammar, inconsistent characterizations, etc., will make readers put down your book unfinished.