Potsdam

As well as the S7, you can take faster RE or RB trains using the same ticket, that stop at major central Berlin stations like Friedrichstrasse, Hauptbahnhof, and Zoo.

What you see in Potsdam depends on what you prefer out of interior palaces or gardens. Most of the palaces are from the Baroque era. Sanssouci itself has timed entrance so you might want to arrange that first.

Hi,

When you get to Potsdam Hbf, the tour buses parked there will be asking you for your business. They are across the street from the train station. I would suggest a tour that includes both Sans Soucci and Neues Palais. If you decide to see the city (Potsdam is one of my favourites in all of Germany) and the sights on your own (I've done both), that's easily done too. Across the street from the main entrance of Potsdam Hbf is a bus depot, signs point out which one to take for which sight.

Potsdam Hbf is large with its underground passage and the variety of shops. I like walking around the streets in Potsdam's Innenstadt, not only in the famous sites eg, Holländisches Viertel (the Dutch Quarter) but also in the non-tourist areas.

I spent most of my time in Potsdam around the palaces and gardens, and didn't really have enough time to adequately explore the rest of the city... which is a shame, because it's one overall a very pleasant place. So, with only one day, I would probably concentrate on the palaces and gardens.

I took the city bus from the train station to the palaces and back again. Perhaps a tour bus might give you a better look at the city, as the public transportation route takes the most direct route, rather than a leisurely stroll through the neighborhoods.