As I wrote in another post for Prague, one of the very best things we did was arrange for tour guides. Through one of our Prague guides, Vaclav Storek, who was recommended in the Rick Steves' book on Prague, we were able to contact Katharina Saudino to help us in Vienna.
We were able to contact Katharina through Vaclav's recommendation, and she also was not only a wealth of knowledge of the history and culture of Vienna, but also of the ins and outs of visiting sites, shopping, dining, etc. All of her recommendations were excellent, and she was able to guide us to the front of many lines (e.g. Schonbrunn Palace, so that we wouldn't have to spend precious time waiting), recommended wonderful (and moderately priced) restaurants to us, and made sure that, when we had things planned without her, that we always knew where to go and how to get there. She helped us with mundane things - where was a good cash machine (and at our request made sure we understood how to use it!), purchasing tickets for events, how to ride the subway, etc. We hope return to Vienna sometime next year, and before we do we will contact Katharina to make sure that she is available to guide us again. She made it easy for us to enjoy our visit in Vienna, and helped create memorable and meaningful memories of what has now become our favorite city - Vienna. We will always be grateful to her for introducing us to Demel's, the scrumptious pastry/coffee haus in Vienna!