Study the query/submission guidelines for the agents and publishers you're targeting. These are published in resources like "Writer's Market" as well as on company websites, and provide contact information, submission periods, desired genres and word counts, and whether recipients want query letters sent solo or accompanied by sample chapters.
Open a new document in Word; set one-inch margins on all sides; and select a 12 pt. font such as Courier New, Bookman or Times New Roman. Use the same font throughout your letter and refrain from applying bold, underline or italics. Cover letters should not exceed one page.
Create individually addressed letters for each person you're contacting. Make sure that names and titles are spelled correctly and include the company's full address. Keep salutations formal until you're invited to correspond on a first-name basis. Incorrect: Hi, Bob! Correct: Dear Mr. Newhart,
Keep subject lines brief. Example: New Book Submission
State your letter's purpose in the first paragraph. Example: The purpose of this correspondence is to query your interest in my recently completed novel, "The Spellbox," a time-travel romance set in my native Scotland.
An editor should be able to tell at first glance why you're writing, and not have to wade through meandering explanations of how you've always wanted to write ever since you were a child, but then you got married and had children and went through a divorce and yadda, yadda, yadda.
Devote the second paragraph to a summary of what your book is about, its target demographic, its length, and how it's either consistent with previous titles that have been represented/published, or resonates with current pop culture/public interest. Example: In these tough economic times, "How to Reduce Your Mortgage Payment to Double Digits" will appeal to families struggling to hold on to their homes.
Use the third paragraph to highlight your credentials and explain how you plan to participate in marketing your book. Example: I teach vegan dessert workshops around the U.S. and plan to sell this book to attendees.
Close with a call to action. Example: I will be happy to send the complete manuscript upon request. Include your full contact information below your name.