It's the one writer whose e-mail really stands out in professionalism that gets the job with me. Just because it's easy to dash off that e-mail, doesn't mean you should leave your professional cap on the hat rack. An editor will pass up your whole idea if there are numerous spelling mistakes in the query to begin with. Finally, don't just read the publication's guidelines. Read the publication itself.
Most magazines have samples on their web sites.
Many offer free samples or those that cost less than if you bought it off the shelf. Guidelines do nothing for what reading samples can do for you. I spoke with tells me how she read the guidelines on a site, queried the editor, got the go-ahead and wrote out some of her best work. Unfortunately, it was rejected because it was completely opposite of the style the magazine uses. She finally made the sale but had to do twice the work to get it.