You Will Need At Least 2 Days to See Berlin. Though a really good visit may take 3 to 5 days to cover the German city, Berlin, you can try and make it in 2 days if that is the time available at your disposal. Most of the attractions in Berlin would have historic connotation, the pre-war Germany and then under the long Communist regime, before the Berlin Wall came down and the city became the capital for unified Germany.
Many people prefer the hop-on hop-off tours, offered by seasoned operators, in the city. The general advice is to go through the full tour the first day without hopping off and choose a few to do a more detailed round the next day. The buses make 20 stops in all, including Checkpoint Charlie and Brandenburg Gate. The interesting aspect of these tours is that you can choose from 13 different languages in which the commentary is made available to tourists. You can then take a Berlin River Boat Tour to top off the trip.
You can probably invest in a Berlin Welcome Card that allows you free public transport apart from free entry to many of the destinations on your tour around the city.
There are hostels located near Berlin Central Station, Alexanderplatz, Brandenburg Gate and Tiergarten.