Gather images. Even if your focus will be written content, magazines are a visual medium. Great images will keep your readers interested and add another dimension to your articles.
Take photographs that relate to your content. Be sure to include photos with empty, neutral spaces; these make great backgrounds over which to place written content.
Make a photojournalism project. This means exploring one topic in-depth and guiding the reader along with a series of photos. This is a good option for people with strong photography skills.
Search for images licensed with the Creative Commons license online. While all of these photos will be free, be sure to read up on whether or not you need to attribute the photo, have permission to alter the photo, or can only use the photo for noncommercial purposes.
Purchase stock images from a stock photography database. While this is a slightly more expensive route, stock photos are taken with exactly this kind of project in mind, making it easy for you to find images that correspond with your content.
Draw your own pictures, or join forces with someone who does. This is recommended for an art-house-style magazine.