Elaborate on your past job roles and discuss as much you on how you have dealt with your clients and customer and always make an example with story where you did your best to help the customer despite the problem could not be solved at you end or if you did solved it then you must add as how you have gone above and beyond to give the customer the vest experience interacting with you. Mentions key things like not interrupting the customer and showing empathy and objectivity and how important is active listening and how you did manage the FCRs and death patches on the call by asking questions and explaining the steps and process through which you were helping the customer. See, the point is that you speak and deliver your message and analyze how well you are being received by the customers. Add places where did you find the area of improvement and how did you communicate the same with your manager and teammates to help you overcome those challenges.