On the first day I introduce texture, tactile and visual. We then roll small pieces of model magic into spheres that we then gently step on to get the imprint of our shoes onto. They love this and enjoy trying different parts to their shoes to get different patterns on each of their pieces.
On the second day we gadget stamped the three secondary colored paints onto three primary colored papers. They love this step as well. We talk about a good composition has overlap, things running off the edges and no big blank areas.
On the third class they trace some freeform shape templates onto the back of their stamped papers,. Cut out each shape and glue it onto black paper. I then set out random stacks of model magic pieces. (They don't get back their pieces because I want them to have a different texture on each piece and not all the same.) They glue their piece onto their collage and then use "glitter it" paint to paint the tops of the texture pieces to cover up the dirt from their shoes.