Next I cut the paper so that it would be slightly thinner than the width of the cardboard strip. In my case that ended up being 3.66" wide.
You can make them as fancy or utilitarian as you like. Here are a few more photos of other more fancy recycled sketchbooks that my friend Nancy and I made. In these examples (below) instead of cutting and stapling we folded the paper and Nancy used a heavy needle and thread to hold the pages in. The possibilities are endless!