Cut the shape of your mirror out of the rigid piece of cardboard. Paint the front & back in an acrylic paint & set it aside to let it dry.
Cut a smaller piece out of a thinner piece of cardboard from a cereal box or something of that nature. This will represent the glass for your mirror.
Glue a piece of tin foil over this smaller piece. Try to keep the tin foil as smooth as possible. Cut the foil to the exact shape of your “glass” piece.
Glue the foil covered piece to the center of the mirror shape. Glue gems or other embellishments around the mirror. Add glitter to pretty up the mirror.
When the glue from the gems & glitter has dried, flip the mirror over & decorate the other side as well. It could be fun to play with this mirror.