There are efficient Bicycle routes through most of Berlin and hiring a bike for your stay can be an interesting and fulfilling way to see the city. Bikes can also be taken on trains and some buses. The cyclist hotline (01805 151 415) will give you information on the rules and regulations to do with biking in the city.
Trams run mostly in East Berlin, and are an excellent way to see parts of the city such as Mitte and Friedrichshain-Kreuzberg. They are bright yellow like the buses but are not double-deckered so easy to tell apart. They are also very ‘hop-in hop-off’ convenient; all transit tickets are valid in trams as well and there are machines on board each one should you need to buy or renew a ticket. A map of the network is also present on each tram and with your own city map, it will be extremely useful.