Instead of flowers and leaves, you can also use firm vegetables and fruits like potatoes and apples. Slice a potato or an apple into two and mark a design on the flesh of the vegetable with a pencil. Carve around the outline of the design with a sharp knife or blade. The design itself should be raised from the background. Brush fabric paint into the cut out vegetable or fruit and stamp it on the canvas bag. Use a variety of colors and designs to make the canvas bag more attractive. For more ideas, go through the Buzzle article canvas tote bags to decorate.
Read more at Buzzle: http://www.buzzle.com/articles/how-to-hand-paint-canvas-bags.html