Go to Hugendübel bookshop near the "Fressgasse" / Hauptwache where they have books about walks in the Taunus.
What you can do is take the Tram to Oberursel - Hohemark end terminus. From there you could walk around the old celtic settlements which are on both sides of the main road (Kannonenstrasse) to the Feldberg. You could also take the steep pathway which starts at the "Heidetränk" (heathens well) and curves up on good paths to the Fuchstanz. At the Fuchstanz there are plenty of places to get something to eat and drink. From there is also a very nice walk to the top of the Altkönig which has 2 celtic ring walls around the top and from one side a good view over FFM.
By the way the Altkönig has lots of heather blueberrys to pluck in september - makes great pancakes
Not far from the Fuchstanz is a place I call Butterfly alley. In the spring you can more or less walk through hundreds of butterflys which swarm all around you.
The restored roman fort at the Saalburg by Bad Homburg is first of all a great place to visit and there are some good walks which follow the Limes (like Hadrians Wall except flat). Bus from Bad Homburg.
At the hotel beergarden next door there are somtimes good blues bands who play on sunday mornings.
I reckon thats enough to get you started.