Designers are getting pretty creative with their magazine covers. Just about anything goes. However, there are certain aspects that should remain in place no matter how creative the cover is. A truly creative person can keep essential elements in place and still be creative. The sample photo used in this article was designed by a creative team, including myself, for SciFi Studios. The actual layout of the cover was done by one of SciFi Studios' most talented artists, Paul Simpson.
Choose an image with impact. Magazines are a visual medium. Inside, there's plenty of both text and imagery. It's all about image on the cover, though. There are a ton of mags out there you're competing with. The magazine has to capture the attention of the potential reader. It has to look good. It has to speak to the potential reader and that starts with the photo (or artwork in some cases).
Pick a photo that will appeal to your target audience. If your magazine is about dogs, you could use just any image of a dog, but that's just not enough. Think about the idea that you are trying to get across. Consider whether this magazine is all about dogs or about an owner's relationship with his pet. If it's the former, a photo of a beautiful dog is appropriate. If it's the latter, an owner and a dog sitting together on a picnic blanket would work better. If the magazine is about relationships, show a relationship.
Choose an image that directly relates to the current issue. As a general rule of thumb, you should choose either an image that relates to the main article in the magazine or the image related to the contents that is most likely to get someone to pick up the magazine. Ideally, it should be both.
Place the logo. You can choose where to put it, but it's nearly always up at the top. Unless you have a very compelling reason to put it anywhere else, leave it there. It needs to be the largest thing on the cover, other than the main image. This is your identity, and it is not to be taken lightly. It's what represents you, and it is the one thing that will remain the same (or very nearly the same) from issue to issue. If this is the very first issue, don't obscure the logo much.
Choose what words and phrases to put on the cover of the magazine. You can put them anywhere, but the most common are to put little blurbs mentioning several of the articles on either side of the main image.
Carefully choose what fonts to use for the text of your magazine cover. Fonts, or letter styles, are very important. They speak to the personality of your magazine. Be a bit creative here. Above all, make sure that the fonts are very easily readable, even for those with poor eyesight. Don't choose a font so "creative" that a person can't instantly read it on first glance.