Using the pliers, carefully remove the hanging apparatus from the Christmas ball.
Apply paint with the sponge to the terra cotta pieces. Don't cover the whole surface; instead sponge the paint strategically. Try for an aged look. Excess paint can be blotted off with a soft cloth. Let the terra cotta dry. If you have aged terra cotta, you can skip this step.
Turn the larger pot upside down, glue the saucer right-side up on top of it, and then the smaller pot right-side up on top of that. Let the glue dry.
Plant the moss in the saucer. An alternative to real moss would be dried moss sold in florist shops.
Put the Christmas ball in the smaller pot, open end down.
Set your new gazing ball in the garden for the "fairies" (and you) to enjoy.