Collect and lay out all your recycled items.
Draw three-dimensional forms on your sketch paper, focusing on the abilities of your various items and how the items can connect with each other. If you want to create a two-dimensional "painting" out of recycled materials, then focus on each item's colors and its ability to lay flat on a surface. Continue drawing and redrawing until you create a satisfactory final image.
Add additional information to your sketch at each "connection point" (where one item touches another). For example, if your project includes two doors nailed together, then write down the projected length of nails you will need on the sketch. Different items will need varying attaching mechanisms. For example, a nail gun might work fine with several large recycled wooden doors, while hot glue works best for plastic cups. Make these and any additional notes on your project sketch.
Create a base for your project: either a stand that will support the weight of your recycled goods for a three-dimensional art project, or a surface for a two-dimensional piece. For a two-dimensional piece, consider using wood, instead of canvas, for the surface to increase the ability of items to stick to the form.
Attach the recycled items to the base and to each other as per your notes.
Place papier-mache, fabric or other material over the parts of the form where you want to cover the recycled elements. For example, if you want to create a tin can horse, but do not want the legs to show, then use papier-mache to cover and form the legs of the horse.
Paint your project and add any surface decorations that you wish.