I was discussing the interview process with a consultant at a Top-10 firm that has interviewed well over 100 students over the past few years. One of her comments? "There's nothing more frustrating than a student who assumes they know nothing about an industry just because they don't know it in a business setting".
The fact is: you know more about an industry than you think. Yes, you might get a case about custom-building high-end cars and you aren't making that kind of money as a student (...yet). The difference between a good interviewee and a bad one:
Interviewer: "What can you tell me about the competitive landscape for this firm?"
1. "Well I don't know much about this industry as I ride my bike to school every day. Can you tell me if the industry is fragment or consolidated?"
2. "Hmm, I can't say this is an industry I'm intimately familiar with, but I think I can make a few guesses at what the competitive landscape looks like. I imagine that it's a very service-oriented industry, with a strong emphasis on providing excellent customer service and high levels of customization that will keep customers happy. I'm also assuming that reputation is important, because of how much a buyer would be investing in making their car purchase. Thus, I'm assuming that there are high barriers to entry for new competitors because they would need to build up both the service levels and the reputation to attract customers."
You know a lot more than you think you do. In an interview, don't make the mistake of asking a scripted question (we've all read Case in Point). Instead, follow the "Assumption-Question" rule. Make an assumption and THEN ask your question. Your interviewer will be impressed that you took the time to think about the topic before asking your question.