Munich has a wonderfully efficient underground rapid transit system: the U-Bahn. It is almost always the fastest way to get to where you want to go. The S-Bahn is an elevated train system, especially efficient for traveling to outlying areas and suburbs. Trams and busses complete the system.
Taxis are easy to catch, but can be expensive. Much of the tourist portion of Munich is easily traversed on foot, however. If you choose a hotel near the Old Town, you can get to most places within a reasonable time frame. Plus, it is by far the best way to absorb the spirit and flavor of the city. You can also rent a bicycle if you want to tour the city on wheels.
There are three tourist offices in Munich, at Sendlinger Strasse 1, Bahnhofplatz, and Marienplatz. Once you are in Munich, they are the best place to go for information to aid you during your visit. Prior to your trip, consider purchasing a good street map and a few guidebooks. Familiarize yourself with the main streets, squares, and subway stops. Once you arrive, you will have a good understanding of the city's layout and you will find navigating the city a much less daunting task.