1) Provide a lengthy summary of the story in your cover letter. Editors always appreciate extra reading, and explaining the story helps stupid editors understand the story they are about to read.
2) Ignore the submission guidelines. Those pesky guidelines are created by the editors to help make the submission process run smoothly and efficiently. If you don't follow the guidelines, it can throw a wrench in the process that makes your story really stand out!
3) Make the first few paragraphs of your story the worst few. After all, its the editor's job to spot the diamond in the rough, and you don't want to make your diamond shine too brightly. Editors love a challenge.
4) Say, "This is the first story I've ever written" in the cover letter. Editors love to know you think the other stories in their magazine look like they were written by beginning writers.
5) In the cover letter, tell the editors the good things others have said about your story. Editors can't tell good stories from bad ones by themselves, so the opinions of unnamed others provides helpful guidance.
Just remember these simple guidelines, and you will be well on your way to papering your office with rejection slips.