Kids love printmaking. It can however be a long, sometimes messy process, and figuring out how to manage the process can be difficult. I love teaching it and have gotten the process down to make it a pretty painless activity.
We used owls as our subject and I placed several different pictures of owls on the tables for reference. I used printer paper first because it is easier to transfer a drawing from a thin paper. I gave each girl a foam piece that was 6" X 9" and they traced the perimeter on the printer paper (this helps them make a drawing that is the appropriate size for printing). The girls then drew their owl--vertically or horizontally--and they could crop it if they wanted. We discussed adding detail and they also had to figure out how to fill the background space.
When their drawings were complete, we taped the image on top of the foam plate. They retraced their drawings, removed the drawing, then used their pencils to retrace the image directly on the foam. Retracing on the foam ensures that the image is deep enough to make a clean print. Make sure your pencils are not too sharp, because they will tear up the foam.
I have learned after many printmaking projects, that having each child print their own print is not as successful as me just printing them all. I always print one in front of them, and show them all the printmaking tools so that they understand the process, but having 20+ students printing at once has proven to be quite a crazy class. Plus, it takes up too much time, and I only meet with them once a week. If I print them, they are guaranteed a nice dark, clean print.