I saw this idea on Make It.. a Wonderful Life but wanted to try it with canvas boards (I much prefer them to cardboard), and using far less steps.. The original poster did this with a children's art class. They drew their pictures on paper, traced it onto tracing paper with ink, then covered the other side with graphite and then traced onto the cardboard. This is a great technique to use, but I just don't have that kind of patience...
What you need
A canvas board (or cardboard)
Tacky glue (other glues will not work)
A glue stick
Something with a dull point (I used the end of a paintbrush)
Shoe polish (I used a sponge applicator one)
Make a design on your board or other surface with the glue. ( I like doing it this way because you end up with maybe some crazy unanticipated design that you will love.) Let glue dry overnight.
Glue needs to be fully dry. Cut your aluminum foil to size (with a border to fold over - about an inch or two). Cover one side (either) with the glue stick.
Press the foil over your design. Push in the edges with your fingers, lightly (you don't want it to tear). After you have smoothed most of the bubbles out, fold your edges over the sides.
Take your dull point and press down around your design. Try to push the excess out. Make designs in the flat foil (this will catch some of the shoe polish later and make your design more detailed).
Apply ample shoe polish all over your design. After a few seconds, wipe off as much as possible with a paper towel.