Avoid obvious questions that have obvious answers.
Ex. "Is Hitler bad?" (We all know the answer to this one).
(:
HE DID NOTHIN WRO
Definitely what everyone else has said. I've come to an interview as of recently and being like you, it was my first one so it was pretty nervewracking but what I did that isn't listed by the others would be to:
Learn abit more about the area you're applying in, so a simple thing such as visiting the place beforehand to get a glimpse of what's new and what's old or what's happening currently could drastically change the interviewer's opinion of you. Something small such as for lack of a better example "Hey, I noticed the new development down at the south east end of the campus what's going to be implemented there?" or something of the sort will definitely separate you from the rest seeing as you did place an interest in the area and went out of your way to find the minute details that people oversee as a tiny detail or whatnot. Keep in mind this is kinda situational, you wouldn't talk about flower arrangement to a teacher or whatever. Just think about it first or something.
With this in mind, it's also kinda neat to read up on body language and semiotics small things such as feet positioning, body curving, eye movement, (keep in mind the rules usually apply, rather than set in stone) could really help you assess the other person quickly. Sometimes what I do, I know it's abit weird but when I'm outside and I see someone or a group of people doing something I try to you know when people like dub over their talking or thoughts yeah I do that silently but in relation to what they're doing and what their body language is saying. Are they standing chest out? Bent over? Slouching? Are they moving out of their way to walk in front of the group? How are their feet pointed/directed when they're facing someone? How do they interact with said person talking? Etc. It's abit creepy but it's kinda fun. I think people call this people-watching, like bird-watching. LOL.
Uh, anything else would be to just really build up your social skills as above said. As much as you study and read up on a place, it's no benefit if you can't handle talking to a crowd impromptu. If it helps, I suggest you google popular interview questions or whatever and just practice practice practice, revise revise revise all your answers and tailor them to suit the question and situation at hand.

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