1. Start your query letter with a description of what the cover will look like.
2.Put (c) year on the title page. Even better is (c) five years ago.
3. Put "do not duplicate under penalty of criminal prosecution" on the title page
4. Tell me your book is a cross between The Electric Church and Sex and the City.
5. Tell me you've queried 10 other agents; include some of their "favorable comments"
6. Tell me your novel is being seriously considered by two major New York publishing companies (and fail to include any further information)
7. Tell me you are famous author's relative (12/9/07 update--that book just sold to the new Borders-only imprint, so clearly, opinions vary!)
8. Tell me you've wanted to be a writer your whole life but you've just now retired and have time.
If you do not understand any of these 8 points, ask in the comment section and I'll yammer on at LENGTH on the topic.