Oh my gosh, yes, I've been there. In fact, I was born there, but left when I was around four years old. Never returned until around 21 years ago. Last visited 17 years ago. In fact, returned home that last time on August 11, 2001, just a month before 9/11.
I'm so jealous that you'll be going. I would loved to have returned again, but circumstances haven't allowed it. If I lived on the East Coast of the U.S. I would have been visiting possibly every year. But living here in the Pacific makes it much harder and more expensive. It actually takes me around 24 hours flight time and layovers to get there. I actually really liked those layovers.
My dad, who was in the American military, met my mother, who was born in Vienna, during the four-power occupation of that city (Four in a Jeep). That's how I got there and how I got here where I live now(after he retired).
As far as what I can help you with, that's really not so easy. It all depends how long you'll be staying and what you're there for. You might like to go to concerts or operas, or to Wine Taverns, or visit museums, etc. There's really so much. I'm assuming you'll be staying in a hotel, and they can help you there. You can take tours (there's a tourist office that can help you). For me, I loved just walking around the City Center. And then visiting more far afield areas with relatives. But my most helpful thing to learn was the public transportation. I figured that out finally by myself. It's great! But one time when I was going to the city center from where I was staying with a cousin which was somewhat near the Prater (amusement park--you must really ride the riesenrad--Giant Ferris Wheel). I got lost and ended up on a some train platform with hardly anyone around to ask, until there finally came a gentleman who knew some English and helped me out. He got me on a train with him and got me to Westbahnhof (the major train station) and we had a nice chat, and told me that he was headed for a health spa. And he gave me one of his tomatoes that he had grown in his garden. Got to Westbahnhof and then we took a glass elevator and he told me where to get off and then we parted ways.
Anyhow, here is an hour and a half youtube program you might like.
https://www.youtube.com/watch?v=AFZBOTgL_Hk
And this one:
http://www.hello-austria.com/
And here's something to leave you with:
