The other point is that the most perfect query letter in the world won't help you if you don't have a strong concept and an excellent book. (accrispin.blogspot.ru)
Fiction Writers Connection — Query Letter Do's and Don'ts Rites of Submission: Cover Letters and Queries by Jacqueline Ogburn Do's and Don'ts How to make the Perfect Query Letter by Gail Eastwood FAQ Query Letters by Tara K. Harper (underdown.org)
He crafts the perfect query letter for you, then selects the right literary agents to pitch to and sends the query out to them. (book-marketing-expert.com)