A Tip for a Tip

Smile about this tip. A basic customer service skill is to smile when you talk to someone on the phone. Why? Your voice has a more pleasant tone when you smile.
Now here’s a tip about that tip. Reinforce using your smile with a mirror. Many folks who talk with their customers on the phone will keep a small mirror nearby. They will see themselves on the phone and discover whether they are smiling. 
Another tip for this tip is to post a smiley face nearby. Instead of a mirror some folks stick a smiley face where they can see it when they are on the phone.
Smile when you are on the phone and watch yourself smile. A simple tip that will make a difference for your customers.