Stencils are a GREAT way to compose drawings, paintings, sculptures, and any piece of art you can imagine. Start by choosing a subject. I shot this photo of Saint Charles' municipal building in order to help out a nine year old student put together an architectural themed canvas painting.
STEP 1 - Choose a subject. Go for a walk, remember conversations with friends, family, students, from the radio, television, funny things you heard and weren't in conversation with, things you observed, etc. Choose something that you've got a lot of interest in, or just can't look away from. You can choose things of power, or go the other direction and choose the powerless. This building really catches my eye, and it's the most interesting thing on the skyline here in Saint Charles. Each day it changes depending on the color of the weather.
STEP 2 - Divide the subject into values. Designate areas of darkest value, midtones, and highlights.
STEP 3 - Cut a stencil for each value; dark, midtone, and light.
STEP 4 - Choose colors that are harmonious, or you can go the opposite direction and make them clash. If you're making something for your mom to hang for a while, she's probably going to prefer harmonious colors. If your mom loves everything you do, then go with the chaotic colors, or just paint it for someone else.
STEP 5 - Paint through the stencils. You can do this with a brush, by splattering, or spraying with a bottle.
STEP 6 - Let it dry!
You now understand how stencils function. Draw and cut your own, use them with different media or the same media. They work really great with watercolor, and oil pastels. Use turpentine with the oil pastels to dilute them and get washes.