In retail or other sales jobs especially on the phone, you can work on changing the tone and inflection of your voice. So while you may call your friend and just say in a monotone “hey, it’s Pete “, when you are selling you are on a stage, so you can act happy and enthusiastic. “Hi Michael, how are you? It’s Pete here.” I know that I speak in a monotone in my everyday affairs without even thinking about it, but when I’m on a sales call or presentation enunciating, changing tone and inflection are great ways to “cheat”.