Just be yourself and have fun!
Your enthusiasm and care for people, and if you’re able to work diligently. It is a fast paced job so being able to learn quickly will help you a lot.
You should bring a resume with you, and focus on mentioning "customer connections", and how you are in fast paced environments- if you are applying at a drive thru location, you should be very confident in yourself when it comes to fast paced environments.
Just be yourself
Understand the philosophy of the company, learn about the position you are applying, be as friendly as possible, know how to multitask and know the different coffees.
Smile a lot
First of all i should be dressed well, entering interview place with a serious smile, brainstorming all what i have informations about types of coffee and the history of it including preparation methods. and for sure i should use my IQ to answer smartly with high subjectivity, credibility and confidence, because that what makes an individual successful in his life.
Read the history of Starbucks, and know what your favourite drink is. And like coffee because you will be sampling it.
Be prepared to answer many questions and imphasize your love for people and of course coffee.