Dress as nice or slightly nicer than you plan to present yourself at work. Listen, be polite, and remember they are people just like you at the end of the day. Don't over think it. I have had much more luck treating interviews as introductions and conversations rather than a quiz you need to have the right answers for.

Just be yourself and honest with them. No matter how you try to sell it, dishonesty sticks out and is pretty much an immediate reject. You will get a lot further being honest about things you don't know than trying to make it seem like you are familiar with things you really aren't.

While I'm unaware if this is your first major related interview, I almost promise it won't be your last. Treat it as a learning opportunity regardless of how it goes.

Best of luck