It sounds like you want to show that you have the skills to work in that call center environment. I can tell you, as someone who has worked in a call center, that customer service, stress management, prioritization, and problem solving all come into play for that role. If you have previous work experience, focus on those areas. It could be that you worked in retail and have experience working with angry customers and make sure the y are satisfied, or worked as a server in a restaurant and had to keep track of four tables of customers at once and provided a good experience. In any case, show that you have evidence that you are up to the task.
If you don't have previous work experience, as Kim said, you can use situations in your personal life to support the same conclusions.