I dressed up for the interview, it's better to look professional because it makes it look like you're taking the job seriously. The woman that called me was very friendly and easy to talk to. She asked me how I was doing in life and what my plans are in the future. She appreciated the fact that I graduated college and had experience as a barista. We also talked politics and current events. As for Starbucks related interview questions, she asked me why I wanted to work at Starbucks, and what I knew about Starbucks as a company. These were pretty easy questions considering that Starbucks is really selling itself as a ecofriendly company. Later on she asked me situational type questions. After the interview, and my free drink (which I received prior to the interview, she described the work uniform and when I was available. Then she said that she would call me the next day if she wanted me. Next day, I got the job :)