A lot of blog posts talk about query letters, but I’ve not seen many on cover letters. A cover letter should be submitted with a short story, contest entry, poem, or requested material. It briefly gives your contact information, an overview of what is attached, and a paragraph about your credentials or relevant personal data.
Although some sites say it isn’t necessary, I’ve always added a cover letter, even when submitting electronically, because it gives my submissions a more professional appearance. It’s a business letter, and serves as an introduction to the piece I’m submitting. Although the article or story needs to sell itself, it shouldn’t have to explain itself.
Once when I sent an article as an attachment, which was the requested method but wrong format (they couldn’t open my Word 2007 docx attachment), the cover letter enticed the editor to ask me to resubmit the article within the body of an email. It would have been easy for her to delete my original email on the assumption that I didn’t know what I was doing. However, since I mentioned my topic, the edition of the magazine I was targeting, and my writing credits in the cover letter, the editor gave me a second chance. She ended up buying the article.
Write a cover letter like you would a normal business letter: single spaced, block format, with double spacing between paragraphs. Include a polite closing sentence, and state what is enclosed—short story name, SASE, etc.
Here are a couple of helpful sites that go into a bit more detail on when to use a cover letter, and what to include: