Well, to be honest we usually limit our advice on transportation portion of any journey, so it is a bit difficult to play a role of a city guide, we simply not that good at that
Although for instance for a day agenda in Prague we would recommend something by foot, for instance
route like this, as you can understand - totally subjective choice and many people would prefer something different. In case of Vienna most the things are a bit more compact, so you can just wonder inside the ring and be sure that you'll find something interesting. Or if to speak about any exact plan, then something
like this for a start, while next you can just make a specific trips to places like Belvedere, Schönbrunn, Hundertwasser spots etc., it all depends on your preferences