If your letter makes you look like an amateur, you have little to no chance of getting approval. Take your letter and make it really perfect with these instructions.
Send it to the right person. Find out a specific name for the editor who handles your type of topic. For example, if it’s a fashion piece, it should land directly in the fashion editor’s hands. This is the one time you can call if you need to - not to speak to the editor directly but to ask for assistance in finding out the name of the editor you want to contact.
Your letter should be completely error-free. This is crucial! Even if you are sure that every word is spelled correctly, every sentence grammatically correct, every punctuation mark included, still get a second party to proofread it for you. Spell-check systems are not fool-proof, and reading your own writing isn’t either. Even if you have a stellar, original idea, if you submit to an editor with mistakes in your writing, your chances of getting the assignment will be significantly lowered.
Include your name, address, phone number and email address.
Stick to one page (one and a half at most). Editors are busy, and they receive stacks of queries every day. Grab attention with yours, but be succinct.
Thank the editor, and include something about how you hope to hear back from him or her soon.
Include your SASE. It is fine to fold it so that it will fit into your envelope.