Prague is an incredibly lovely place to visit. It is packed with historical sights, beautiful views, and lots to do. If you are planning a trip, I suggest the summer months or early fall, as it is sunnier- but winters here are very mild (this is coming from a Chicagoan, though).
Before you come, I suggest deciding how you plan to get around the city. The public transportation is really great. If you are hear for just a few days, you can get tram/metro tickets in a flash using this app. If you plan on staying a bit longer, it’s worth investing in an OpenCard, which gives you unlimited rides for a set amount of time. Either way, if you plan on taking public transportation, this app is a life saver. And if you just want to get around, this app shows you places to go, and how to get there. Have fun!