First of all, they ask you the general questions.... Why do you want to T-mobile? How can you help advance our team? Then, they get into senerios where the interview pretends to be a customer.... Basically, he/she is looking for eye coordination and confidence in your answer. My advice is to know the products and competitors before the interview. Most applicants have been in the business and looking for a change. Be a customer and communicate with a sales rep before the interview process.