Place the stencil of your choice over the center of one of the sides of the terra cotta pot. Position it so that it is centered over the broadest area. Stencils vary in design immensely; you can find them decorated with flowers, butterflies and other symbols or designs.
Adhere the edges of the stencil to the terra cotta pot with masking tape. This keeps the stencil in place without you having to hold it with your hand.
Outline the cutout portions of the stencil lightly on the pot with a fine-tipped marker. Black is an adequate choice but any color that shows up over the terra cotta works as well. Pay attention to detail and outline every part of the stencil that is cut out.
Remove the stencil. This exposes the stenciled outline so that you can fill it in decoratively with acrylic paint. It's easier to paint the decorative design without the restrictive stencil in the way.
Use the paintbrushes and acrylic paint set to color in and detail the stenciled outline. This is where you are able to express your own creativity. For example, if the stenciled outline is a rose, you can fill in the blossoms with a flat red shade, then fill in the stems with a deep green tone. Create shaded details by blending lighter shades of green and yellow into the stem. Detail the blossoms with shades of pink and white. You can either dab the paint on with the brush firmly, or use sweeping movements to create differing textures in the paint. Use your imagination.