So, it is imperative that your tone of voice convey a friendly, positive attitude. Since none of us are always going to feel upbeat and full of energy, we sometimes have to be good actors and fake it. When the phone rings, put on a happy face. While talking to the customer, force yourself to smile. It is amazing how this visual cue will improve your tone of voice.
Customers just love to be complimented.
Their feelings towards you improve immediately and your feelings improve. Talk more slowly. Really listen to the customer. It is important that the support tech keep control of the support session in order to keep it as brief as possible while at the same time giving good service. Have the customer describe as succinctly as possible the problem or question.