One of my posts earlier this week (that argued most prescriptive nonfiction books have great info, not great writing) sparked a wonderful comment from Deborah that I wanted to bring to everyone's attention—because, as she says, this might be the most important point of all:

This explains why I have so many personal rejection letters that compliment my writing and my organization -- and some even end with, "I hope to work with you in the future," but I still don't have a book credit.

The real gem of this post is within the parentheses of the last sentence -- a book proposal is like a business plan for a book idea. I've recently asked a couple of published friends if I could see their proposals, and I was left with my chin on my chest in awe over their marketing plans. After reading them, I realized that my little page-long marketing plans seemed really vague and incomplete compared to their plans, which were three for four pages long and filled with VERY detailed information (names of contact people, venues for speaking, etc). When I read this post, it clicked that they had written a business plan for their books.

Put another way: The No. 1 thing an agent or editor looks for in your book proposal: why your book will sell (turn a profit) and why you're the perfect person to market (sell) it.

Many thanks to Deborah for her insight!