Are other books available on the same or similar topic? What makes your manuscript different or superior? (Perform a search of books in print at Amazon.com if you are not sure).
List your credentials and experience in relation to the topic of the book. Do you have experience speaking, teaching or writing about this or similar subjects?
Do you have a marketing plan for the book? A web site (list URL)? Speaking or networking opportunities to promote the book? How many copies do you think would be purchased based on your personal and professional contacts?
How many pages is your manuscript? Which word processing or page layout program is it in? How many graphics, photos or illustrations are necessary for the manuscript? Is the manuscript finished?