Most interview questions come from an interviewer's concern with three mega-questions:
What can you do for us?
Why do you want to work with us?
What are you like once we've gotten to know you?
If you want the job, it's to your advantage to volunteer a lot of relevant information about each point, whether you're asked for it directly or not. Since you have limited time during the interview itself, prepare by doing a mental inventory of things you'd like to say if you get a chance. This will help you use the limited time to best advantage.
(1) What can you do for us?
(a) What in your educational background is relevant?
Think about everything, the obvious, such as coursework and research projects, and the less obvious, such as the fact that you've done course projects in teams comprised of students from all over the world. Don't forget those things which you may have learned on your own.
(b) What in your prior experience is relevant?
What have you done up to this point that has similarities to what you'll do in this job? What have you done that may not be directly analogous, but is so impressive on its own that it will support the impression that you're capable of lots of things?
(c) What special knowledge can you bring to the job?
Consider both things you know and ways you've learned to quickly find out. Also consider your familiarity with different types of people and environments.
(d) What discrete skills can you offer?
These may be "hard skills", such as "ability to program in S+" or "soft skills," such as "ability to quickly establish rapport with strangers." Both are important.
For your "dream" job, what's your one-sentence answer to "What can you do for us?"
(2) Why do you want to work with us?
Why are you interested in this industry?
"Industry" can be used generally, so that "arts organizations," for instance, can also be an industry. What can you say that shows you know something about the industry?
Why are you interested in this particular organization?
What can you say that shows you know something about the organization?
Why are you interested in this part of the world, or country?
What can you say that indicates that you have some familiarity with it?
What are your immediate and long-term goals?
(Obviously, it's helpful if these seem to include the job you're interviewing for!)
(3) What are you like once we get to know you?
How do you describe yourself?
How would your friends describe you?
How would co-workers describe you?
How would a supervisor describe you?
For every general positive quality that you mention in answer to the above questions, think of a "story" that will illustrate that quality. For example, anyone could say they work well with other people. What makes the claim believable is an account of a challenging situation involving other people which you handled well and with enjoyment.
(Hint: if you naturally make positive comments about other people as part of your discussion of all all your experience, you'll sound easy to work with).