One of the best things we did was to engage tour guides to help my husband and I get to know Prague - we contacted a few listed in Rick Steves' Prague Guidebook and had great success. We had two - Darina Krajakova and Vaclav Storek, for four hours each on two separate days, at reasonable rates.
Not only were these tour guides extremely well versed in the history and culture of their respective cities (and all spoke English beautifully), they also helped bring to life the experience of living in them. We had asked DarinaKrajakova to take us to, among other sights, the Museum of Communism, and her own stories helped us to understand and appreciate the recent history of the Czech Republic so much more than having toured on our own. When we asked her to take us to lunch somewhere, it was to a beautiful restaurant that had medieval cellars open to the public - not a place we could ever have found on our own (the food was great and very reasonable, too!). She was always happy to be of help - whether assisting us in purchasing concert tickets, or recommending other restaurants and sights for us to visit.
Vaslav Storek's knowledge of history and architecture were limitless, and he knew exactly how to manage to include all of the sites we wanted to visit with him in the half-day tour we had requested. He led us through the Prague Castle complex so that we were able to save time by not having to wait upon lines, and pointed out unique and little known aspects of the history of the sites that our previous research had not uncovered. Both he and Darina were also a font of useful information for the mundane - where is the best cash machine for us to use (and they took us there to make sure we knew how to use them), what is the best taxi company to use, how should we get to the train station, how much time to allow to get there, etc. Should we return to Prague, the first thing we would do would be to email both Darina and Vaclav to make sure they were available to guide us again. They made it easy for us to enjoy ourselves, especially as we did have trouble with the language (we tried to use our little phrase book but couldn't get the pronunciations right!), and helped create meaningful, happy memories of a beautiful city.
Like so many other recommendations in Rick Steves' book on Prague, the experience with these guides was truly wonderful.