Collect several different-shaped leaves from nearby trees. Place them flat between the pages of a magazine. Stack several heavy books on top of the magazine. After twenty-four hours the leaves will lie flat. Put the flat leaves on a sheet of plain paper. Experiment to find the best arrangement. Then you are ready to make your design.
Thinned poster paint in a spray bottle will make a good spray paint. You could also use poster paint, an old toothbrush, and a wire screen to spatter paint.
Place the paper with your chosen leaf designs on newspapers before painting. Spray paint carefully so that you do not disturb the leaves. Wait until the paint is completely dry before removing the leaves from the paper.