Assuming it's a nice day, take the LH bus and get off at the schwabing Nord stop. Cross over into the englischer garten and just stroll down towards the center of town. Stop for a beer and a snack at one of the beer gardens (chinesicher turm being the largest and most famous, well worth seeing), then at the bottom of the park enjoy the surfers on the eisbachwelle. Turn right and if you're into contemporary art the Haus Der kunst is very good. Go through the hofgarten, see odeonsplatz and the feldernhalle.

At this point depending on how much time you have left you can either jump on the ubahn to return to the station to catch the bus back, or keep on walking along brienner strasse, karolinenplatz, the Nazi museum (also well worth a visit) and köningsplatz. Here turn left and walk down luisenstrasse towards the station. Another option from odeonsplatz is to keep walking south to marienplatz and the viktualienmarkt, but honestly I find them very overrated and way too touristy.