Preparing for an interview

Hey guys, I need help preparing for an interview. This is my first big job interview and I'm nervous to say the least. I really want to do well since a friend of mine recommended me for the job and I don't want to let him down. I am curious as to what questions are going to be asked and what I should prepare. Also, if I have a beard, should I trim it, or shave it off.

Thank you guys in advance. I really just want to do well in the interview.

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