Choose one or more stencils from a hobby and art supply store or by finding them online. Generally a design with a definite upper and lower edge will give you a great result. However, if you have chosen a design that does not have a solid line at the top and bottom, consider purchasing another smaller edge design that can be used above and below your main design.
Mark the wall using the tape measure and watercolor pencil. If your stencil is a foot long, then place a pencil mark every foot so you may connect the design easily. Chair rails are typically 32 to 36 inches from the floor and may vary in depth, so mark the top edge of your planned design.
Spray the back of your stencil with stencil adhesive. Place it on the wall and secure it with a few pieces of masking tape. Use a level to be sure it is even. Draw any registration marks on the wall so you can place the stencil with precision when you move it to the next spot.
Squirt a small amount of craft paint onto a plate. Fold a paper towel into fourths. Dip your stencil brush into the paint and load just the tips of the brush. Swirl the brush on a clean part of the plate to remove excess paint. Then swirl it again on the paper towel to ensure that you have an almost dry brush.
Use small circular motions to stencil your design. Press harder around the edges and softly in the middles of the design to create a more three-dimensional look.
Remove the stencil from the wall and place it on a sheet of paper. Wipe the front and back lightly with a clean paper towel before you place it on the wall to continue the design across the entire wall.
Create a shadow effect once the main design has dried by replacing the stencil about 1/4 inch below the first placement. Use a soft grey color to stencil the bottom edges of the stencil.