Some things to keep in mind as you design your zine pages:
Unless you're printing out your zine in color (which can get expensive quickly), your pages will be printed in black & white. Think about the post-print legibility of colors, patterns, and images you use. You might try copying, scanning & printing sample pages as you go to see how they look.
Copy machines often cut the edges off of pages, or impose small margins around the edge of copied pages. It's a good idea to leave a small margin (1/8-1/4") around the edges of your pages to allow for this.
If you're laying the zine out by hand (instead of with software), only decorate one side of each page. This will make your layout process much less tricky.