Pressure-wash your fence and fill any blemishes on its surface with wood filler.
Mark a sheet of drawing paper with a grid of 1-inch squares. One square inch on your paper will equal one square foot on your fence.
Draw a sketch of your design on the paper grid and color it in lightly with colored pencils.
Apply two coats of acrylic primer to your fence with a roller.
Apply one coat of acrylic-based exterior white paint to your primed fence with a roller.
Use a level and dark chalk to draw a grid of 1-foot squares on your fence.
Using your small drawing as a reference, copy the drawing, square by square, onto your fence in dark chalk. If you transfer your drawing one individual square at a time instead of viewing the drawing as a whole, it will be easier to copy onto the large grid.
Paint in the chalk outline with the outdoor-use acrylic paints. Match the colors used, square by square, to the colors used in your small drawing.
Paint two coats of acrylic varnish over the fence with a roller to protect your painting from the elements.