Beautiful city - I want to live there.
Prague is a very cultural place, so not for those who want to sit around doing nothing. So much to do! There are various excursions whether it's a boat trip on the River Vltava, a ghost walk or a segway tour around the city. It's very beautiful, so some form of tour is definitely recommended to make sure you see as much of it as you can. Also, if you enjoy a good night out, there are various kinds of bar crawls, and so many different themed bars and clubs!
Insider Tip:Remember that Prague is popular for stag dos and hennights - there are a lot of people who go there purely for the nightlife. If you aren't interested in this kind of scene, then Prague at night probably isn't for you.
Another tip: speak to the people where you are staying about where to eat, as there are so many places to choose from it becomes an impossible task to make a decision!