If you travel by plane
From Tegel Airport the price for a cab (taxi) is around 30 €.
From the Airport Schönefeld about 45 €. Travel by public transport is also possible but more complicated because of having to change trains and buses.
If you travel by train
From the main train station (Berlin Hauptbahnhof) you travel one station to “Friedrichstraße” and change here to the S1 (Berlin Train Service) direction Wannsee. In about 22 minutes you reach the Station “Lichterfelde West”.