Establish tone, style and intrigue immediately. The most important aspect of your query is the hook -- the first sentence that piques the editor's interest in reading on. Grab the editor's attention immediately and encourage him to read on. Hint at what your story is about. Lure the editor into your story with a strong opening and good writing.
Keep it simple. Don't write lengthy paragraphs detailing every nuance of your story. Make it short and sweet and keep the editor hanging. A hook should be, at best, one or two sentences that tantalize the editor and leave him wanting more. Don't give away the store.
Use the most important elements in your story to develop a good hook. Every story is different. Consider what the most prominent elements of the piece are, including characters, conflict, setting and action. Build your hook on the basis of these elements.
Think headline when composing your hook, and consider which few words would draw you into reading the story if you were the reader. Write a titillating header, and expand it to experiment with your hook. Breaking your hook down into headline form can help you edit out unnecessary verbiage.
Know your editor. It's key to be familiar with the publishing house, publication or website where you are pitching your manuscript or idea. Research the company to see what types of material it usually publishes. Familiarize yourself with the company's target audience. Obtain the publisher's editorial guidelines before submitting material to make sure it's in the proper format.
Address your query specifically to the appropriate editor with the power to make decisions on submitted work. Never send a query to "Whom it May Concern." Use the editor's name and proper title. If you don't know the right person to submit your query to, call the publication and ask.
Include information that proves your background and writing skill. Your credentials are your best selling point with most publishers. Include clips or links to work that you have already had published, especially anything that is appropriate to content offered by the publisher in question. Provide a brief biography, citing all your professional writing experience. If you don't have professional experience, include experience with the topic at hand to prove your expertise with the subject; include this even if you do have credentials.
Provide contact information at the top of the query. Include your name, phone number, address, email address and the date of the submission. Use your name and email address again at the end of the query.