Begin by gathering your ingredients. To cover a standard standard-sized 9 or 10-inch cake with fondant, you will need approximately 2 pounds of fondant. You can use purchased fondant (be sure you get "rolled" fondant as opposed to "pouring" fondant) or you can make your own. If you want to make your own, I recommend trying these recipes for Marshmallow Fondant or Rolled Fondant.
In addition to the fondant, you will need a cake that is covered with a layer of buttercream at least 1/4-inch thick. This frosting layer helps the fondant stick to the cake and smooths out any bumps or imperfections on the cake surface, so the fondant layer looks clean and smooth. You will also need cornstarch, vegetable shortening, a rolling pin (preferably nonstick) and a large, smooth work station.