Wash the wall with mild detergent and water. Dry it thoroughly before stenciling. Add a fresh coat of paint if the existing paint is damaged or fading.
Draw your design onto the cardboard or plastic with a pencil. Draw only the outline of the design. Cut out the design along the lines with a sharp craft knife to create the stencil.
Spray the back of the stencil lightly with spray stencil adhesive. Press it onto the wall to adhere. Tape the edges of the stencil to the wall with painter's tape.
Dip a foam dauber brush, which resembles a flatten ball of sponge attached to a handle, into your paint. Press the dauber onto the stencil, daubing the paint over the stenciled area until it's evenly coated with paint. Daub on a single paint color until all areas of the stencil requiring that color are coated.
Allow the paint to dry completely for 30 minutes to one hour. Using a clean dauber, apply the next color required for the stencil, if applicable. Repeat the process until all colors have been applied.
Peel the stencil from the wall after all the paint has dried completely. Wipe away any adhesive residue from the wall with a damp cloth.