Inspect the surface for damage, scratches or other imperfections. Repair the surface so that it is perfectly smooth, using wood filler, and sand it smooth when the filler is dry.
Clean the surface with a wet sponge and allow it to dry completely.
Paint on the first coat of dark-colored paint with a paintbrush or paint roller for larger surfaces. Allow it to dry according to the manufacturer's instructions and apply a second coat to ensure thorough coverage.
Apply a thin coat of crackle glaze compound over the painted surface using a foam brush. Leave the glaze to dry overnight or for at least 10 hours.
Cover the crackle glaze with a lighter-colored coat of paint. Apply it very thickly and let it dry completely. As it dries, it will start to crack and have an old, weathered look. The thicker the paint coverage over the surface of the glaze compound, the larger the cracks that form.
Paint a final coat of clear acrylic sealer over the crackled surface to protect the finish and keep the paint from flaking off.