Wash the rocks using mild soap and water to remove dirt. Let dry.
Spray paint the rocks with white spray primer. Give several coats and let dry.
Paint the rocks with a coat of yellow and let dry. Don't forget to get the sides a little.
Flip over and paint on the other side. Keep repeating this process of painting each side until the rocks are covered. Let dry.
Draw details on the rocks with paint pens. Begin with a pencil, and get your design sketched out. Then trace the corresponding area with paint pens and color in.
Seal with several coats of Mod Podge and let dry completely before displaying in your home or garden.
Notes
Tip: Use a small paintbrush to touch up any areas on your rocks that need it.