Some artists create images on their canvases by decoupaging smaller images together. From far away, the art looks like a face or a landscape, for example, but on closer inspection the viewer realizes that the large image consists of hundreds of smaller images. To do this, you sort the images into piles. The darkest images go into a pile; the lightest images go into another pile and so on. Then you sketch an image on the canvas. After the sketch, you decoupage the darkest images to the area of the larger image that will be in shadow, the lightest images to the highlighted areas and the rest of the images to their corresponding tones.
There's no need to make your decoupage look realistic. You can decoupage an abstract artwork, instead. Start by tearing textured pieces of paper into shapes you find interesting. Clip out copyright-free images from out-of-publication books or printouts of clipart. Arrange the pieces of paper and images on your work surface until you get an arrangement you like. Decoupage the arrangement to your canvas.
Canvases that are decoupage can also be painted. Combining decoupage with your regular painting techniques can yield interesting results. Try decoupaging images on top of a painting or painting on top of a decoupage image. The best type of paint to use for this type of multimedia art is oil or acrylic. Watercolor paints are not recommended because the glue used in the decoupage will resist the paint, making it bead or run.
Another spin on mixing decoupage with painting is creating texture. Tear paper that has an interesting texture into pieces. Decoupage the pieces to the entire canvas and paint on top of the pieces when they are dry. This will give your painting an interesting texture that will add to the visual interest of the work of art.