Paint your stepping stones with outdoor safe paint. You can paint a single stone or a dozen, and use whatever designs you like. Painting stepping stones is an enjoyable family project. Paint with an outdoor acrylic paint, which comes in a range of colors and is found at any craft store. For best results, paint your stepping stones with a coat of white first so that colors will show up well.
Use broken bits of china and tile to make a decorative pattern on your stepping stones. If you have recently finished a tiling project, save the small bits for decorating your garden. Start a box for broken plates, or head to the thrift shop and pick up a few inexpensive plates or platters in bright colors to work with. You can find mosaic books and supplies at the craft store, but the basic process involves breaking the china and tile into small pieces, gluing it to the stepping stones and grouting between the pieces. Don't use china cups or bowls for stepping stones; the rounded edges can hurt your feet when you walk on the stones.
Add a multitude of small items to decorate your stepping stones. You can use smooth river rocks, small sea shells, plastic gemstones or even plastic toys. Buy a 1-lb. pot of tile adhesive and a plastic spatula from the hardware store. Apply a 1/2-inch layer of adhesive to the stepping stone as though you are frosting a cake, and press the items into the adhesive. Once your stone dries, the adhesive is permanent. This type of stepping stone adds a whimsical touch to any garden, but isn't functional for walking on if you use a lot of dimensional items.