Assemble a variety of dried leaves and twigs around a canvas in the size of your choice. Create an outline around the edge of the canvas with some twigs, and work layer by layer inward until you get to the middle. When you are setting down the leaves, make all the stems point in the same direction so that the piece looks balanced and not chaotic. Leave a 4 inch area in the middle blank.
Arrange some dried, pressed flowers in the blank middle area of the canvas. You can choose to use one large flower or multiple smaller ones.
Go through the entire piece, once again starting on the outside and working your way in, and secure each piece of natural material with some glue. Allow the glue to dry completely.
Spray the art piece with a layer of clear sealant spray to ensure the collage won't flake, crumble or fall apart easily. Allow the spray to dry.