There is a lot of research related to finding the right employees for various jobs. Happily, finding the right people for Customer Service positions is not complicated. Hard? Yes. Complicated? No.
The number one attribute that service employees must have (not optional) is an innate desire to serve. They must offer themselves to their customers. It is not enough to be able to serve (which many of us can do). Their psychological DNA must contain an inherent need to please others. These people are the face of your company. They get phone calls, chat requests, and emails only when something is not clear or has gone wrong. Whether or not they successfully solve an issue is the difference between a [repeat] customer and a defection.
Some schools of thought start with technical or subject matter prowess. But technical people with no service skills should work [well] behind the scenes. They’ll be happier and your customers will be happier too.
As I mentioned, this process isn’t complicated. But it is hard to find qualified people because customer service positions have been maligned and outsourced. Passion isn’t a commodity. As a result, people who love to serve are 1) compensated so poorly they seek other positions and 2) early candidates for outsourcing. Don’t be fooled – low cost service provided by the wrong employees holds no value and your customers know it.
When you do find a candidate who can blend subject matter expertise with service passion, hire them and keep them!
The pivot point is that customer service employees must truly love serving others. That skill alone is the key on which all other service attributes (phone etiquette, time management, communication, etc.) can be built. A man I know often says you can’t teach height [to basketball players]. You can’t teach a passion for service either.