I love this assignment. Each year I have my non-drawing students enrolled in a crafts class create collages from the ripped up pieces of everyday magazines. I stumbled on this technique about 15 years ago. At one time, it was all I did artistically. I entered and won two big collage competitions using this technique. I have two 4' x 8' collages hanging in the Oklahoma Historical Museum. I even collaged on top of a life-sized, fiberglass pig statue for a local event. That huge pig is now at the national office of a pork producers association...I'm not sure where.
My students get to pick their resource picture and since this isn't a drawing class, I permit them to project it on a full or half sheet of foam board. I push them to select colorful images with lots of details. They then start ripping and gluing. They are required to cover the entire surface of the board and they must learn to navigate working on a table easel.
I have an exception group of students this year. They are doing some beautiful pieces that I think will be "frame worthy." I often take some of the top pieces to spring competitions.
Here is one of my torn paper collages. This version of Mona hangs over my desk in my classroom. She was one of my earliest pieces using this technique.