The query letter can be (is) the most daunting task of getting your novel published. I'm still learning how to perfect a query letter...and I only have 1 darn completed book. (I'm already stressing the query for my next sci-fi epic novel.)
Querying is a one page letter about your book you write to agents seeking representation of your novel. Some publishers also request querying first. The basic framework of a query letter:
Most importantly, make sure you put the name of your book, word count, and genre in the query letter. This can be either in the first paragraph or last. Tip for you, not in the middle. It'll get lost.
Paragraph 1: The Intro/Hook (Keep this paragraph only 1 or 2 sentences...I know, I know, but it's important.)
Paragraph 2: Summary of story (It's good to keep this 1 paragraph, but I've seen 2 paragraph successfully done.)
Paragraph 3: Biography (Only those things that tie to the story or you as an author. Not about your life as a kitty wrangler if the story is not about kitty wrangling.)
Closing: Say thank you for time and consideration. ENTER. ENTER. Sincerely, Your name. (Keep it professional people; no begging or bribery here.)
Sounds pretty simple, right? But trust me and thousands of other querying writers, it's very hard. No cliche sentences. Interesting without being corner. Professional without boredom. Courteous without brown nosing or "bowing down to them"...and the list of "eeks" goes on.
There are some great resources to help you get started putting a query letter AND see examples of not-so-good ones:
Agent Query's "How to Write a Query"
Guide to Literary Agents "Successful Queries" series
Good writing all!