What skills do you possess that you believe will help you sell?

It might be helpful to look directly at the job posting before interviewing and look at the 1st 4-6 skills they have listed and discuss those. You also might want to think about skills generally sought after in sales and discuss those. Common skills needed for sales are communication, adaptability, relationship building, and the ability to work independently. You want to be confident in discussing these skills too and show you know you'd be able to perform the job well because of these.