I'm going to be frank here. It has nothing to do with coffee. Whats going to decide on you getting this job is how excited you'd be to meet new customers. I'll give you two scenarios.

1). If it's an extremely busy chain cafe in the center of the city with long queues, they will want you to be as friendly and as relaxed as possible with your customers, despite the fact that you are under pretty strong stress of whipping out 4 different orders at once, and someone asks you a retarded question when they can see that you're busy like 'is the mocha the chocolaty one' when it's right on the menu. This will happen a lot, and honestly the only way to win is not be irritated by it.

2). The other scenario is a local, quiet cafe. In this, you must treat every single customer like you're welcoming a good friend into your home. Big fucking smile on your face when they walk in, greet them super fucking warm. Like lava lamp tier warmth. Ask great questions about their day make them happy because a stranger likes them. Maybe they won't even return the smile but they'll feel good that they got it and that's what's gonna bring them back next time.

If you're anxious about your coffee knowledge, just be aware that 90% of all of your orders are going to be Lattes, Cappuccinos and Americanos.

Lattes = is generally a tall glass of hot, not frothy milk in which an espresso is poured into the tall milk.

Cappuccinos = it's like a reverse latte. This time, the milk IS frothy, and it is poured AFTER the espresso has been poured into the (normal) mug. Sometimes chocolate dusting is added at the end.

Americanos = basicly for people who can't handle espresso, which is what the Italians coined the American invaders's favorite drink in ww2; an espresso topped up with plain hot water. Often served with milk at the side or inside.