Upon arrival at airport buy a transportation pass for the days you need.
We never went beyond Zone A, but if you plan to travel nearby (Potsdam, Charlottenberg Palace, e.g.) a Zone B ticket might be better. It works for all forms of public transport, including busy to/from airport. The public transport system is excellent. Pick up one of their good maps at the ticket booth.
The no. 100 bus does a good touristic route around the city. We often just hopped on a bus when we got tired of walking.
Check out the museum pass good for most museums. Aside from the obvious biggies, we liked the Bauhaus museum.
We loved the Hotel Funk (ask for room 12) old apartment, former home of silent movie actress Asta Nielsen, http://www.hotel-pensionfunk.de/. It’s one of the only old-time hotels left in Berlin.
We also stayed in a lovely shared apartment in Kreuzberg with an engaging couple from Madrid. Lots of good ones on http://www.airbnb.com
Berlin Food Blog: www.thewednesdaychef.com
Borchardt, fancy restaurant (we didn’t eat here, but it looks amazing and $$$ if you want to splurge)
Augustiner, Charlottenstrasse 55, Mitte, old-style beer hall, good food & ambience.
Marjellchen, (our favorite) Mommsenstrasse 9, tel. 030-883-2676 in Charlottenberg—be sure to have the beet soup
Markthalle, Pucklerstrasse 34, Kreuzberg (www.weltrestaurant-markthalle.de),
homey place, good schnitzel, half-portions available…and recommended.
Rogacki, Wilmerdorferstrasse 145, Metro Bismarck
Deli with amazing array of German specialties
Food hall at the KaDeWe department store, 6th floor (Wittenbergplatz)—a must!
BEST NEIGHBORHOODS FOR WALKING:
Schöneberg, a lovely walk: from the U train stop Nollendorfplatz walk south along
Gleditschstrasse for a mile or so. Barbarossastraße was particularly pretty.
Charlottenberg is the fancy part of town (Ulandstrasse station)
walk around Savignyplatz. Kurfurstendam is the main drag, with pretty side streets.
Kruezberg is hip and young, full of international restaurants. Oranienstrasse is a main drag, so wander from there.
Mitte, central Berlin, Unter der Linden, not the loveliest part but has themuseums, opera house, big tourist spots. The music store Dussmann (Friedrichstrasse 90) has a huge selection of classical CDs.