I made my collage the art trading card size, 2.5″ x 3.5″, but it would look great at any size.
1. Find an old phone book or equivalent, and paint the pages different colors with watercolor. Let dry. 2. Cut up the paper to make a simple house collage. 3. Glue all down with a glue stick. 4. Trace around the edge with a black Sharpie marker.