For cheerful containers, stain pots in colors that complement their contents. Terra-cotta is very porous, so it's important to use materials that won't harm the plants, like the all-natural powdered pigments shown here.
Mix pigment with matte medium (a paint extender available at crafts and art-supply stores) to desired shade -- we combined shades of blue, purple, and white -- and add a little water to thin the paint as necessary, making it easier to apply. It's a good idea to mix a small amount first to find your perfect color, then increase the proportions for a bigger batch. Use a foam brush to coat the outside of the pots (one coat will do), then let them dry overnight. The pigments are strong and will stain your clothes, so mix and apply them carefully.
To hang a pot, just fasten a clamp-on hanger to the lip, and suspend it from a nail or screw on the wall.