Before you touch a wire in an appliance, how should you make sure that it is not energized?

Before you touch a wire in an appliance how should you make sure that it is not energized

Before you touch a wire, make sure that it is unplugged first. See to it that your hands are dry when holding it. Inspect the whole wire of the appliance if it has worn out insulator. If it does, wrapped it with enough electrical tape to cover the spotted area.