The tagline on a magazine goes under the masthead, and sometimes can be attached to it. It will either show what the magazine is about or who its aimed at. For example Q's tagline is 'THE ULTIMATE ROCK 'N' ROLE'.

The central image is the most important part of the front cover on a magazine as it's this that catches the readers eye. The image will be relevant to the magazines purpose, audience and it usually strongly related to the main article within the magazine. Alot can be denoted and connoted from the central image.
*Denotation - what you can see thats obvious.
*Connotation - idea that you take from the image,
                         - the way you interpret an image.

For many magazines a cover model is used, usually a celebrity or well-known individual that is connected with the magazines genre. If a magazine has a well-known celebrity on the front it will help the cover sell because they have their own connotations for example people might expect to hear about fashion from Victoria Beckham. Photographic models also help sell the magazine because people that "it could be me".