The best way to improve customer service is to invest in your own team. When you take care of your team financially, and professionally they will take care of the customer. If you pay your associates a reasonable wage for the business and for them, and train them to be the best person they can be, they will pass that on to the customer.
A team that knows their leaders support them will be loyal and productive. When they are happy the customer service naturally improves. They're proud of where they work and in many ways want to show off. This is done at the store environment or over the phone. Associates want to feel important. They want to know you care about them as people, and if your team doesn't feel taken care of or appreciated it will roll downhill.
We all know the phrase about what rolls downhill. I have been involved in team meetings where the discussion is about how we need to improve customer service and then they read all the bad things the customers say, and then the team gets sent out to take care of the customer. Here's the problem. They're angry at the customer.
What rolls downhill doesn't stop with the hourly associates. It stops with the customer because the team passes their frustration down to the customer which becomes bad customer service. I believe if you have bad customer service it begins with management. Don't get me wrong there are customers that will complain no matter how much you try to help them. However, if your team is happy it will reflect in how they represent the company which will determine how they take care of the customer.