There’s a lot of info on the Internet about writing query letters for novels. Some of it sounds contradictory, even after weeding out tips best applied to nonfiction books. The most refreshing and fun method I’ve ever read is in THE LAST QUERY: A New Approach to Crafting a Novel Query Letter by Cindy Dyson.
I met Cindy on another writers’ forum. In time, I had the pleasure of reading her novel, AND SHE WAS. In her how-to book, THE LAST QUERY she documented the process she used to hone her query, written in the same lyrical prose that hallmarks her novel. That query letter hooked agent Marly Rusoff, who sold AND SHE WAS to Harper Collins. http://www.cindydyson.com/shopping.html
I hope this helps a bit with the frustrating process of shifting from writing fiction to writing a query letter, which is basically a business letter.
Ashling aka Janice Wiley-Dorn