I was prompted to think about this question by a recent poll that has placed Germany as the most "positively viewed country" in the world for a second year running. It strikes me as odd that 70 years ago today, Germany was almost universally reviled in the Western world and was in large part responsible for the decimation of much of Europe's population, as well as arguably the most well-known genocide of the 20th Century. How did Germany go about reconciling with other countries (specifically close neighbors such as Poland, the USSR, France, etc) immediately post-WWII up until 1994? I'm interested in both East and West Germany.
There were a variety of factors that helped rebuild relations between Germany and its neighbours in the period after the war. To make a generalisation it was a mix of both practical and political reasons, but also the fact that (at least from the late 1960s) West Germany was reasonably open to admitting its crimes and open about its responsibility.
The influence of the Cold War meant that for political and strategic reasons, it became 'necessary' for nations to work together against the opposing alliance. This meant that at a political level, it became convenient to look past issues of what had occurred during the war and work towards common goals. An example of this is the integration of West Germany into NATO - while this was borne out of the failure of the European Defence Community, both West German entry into NATO and West German re-armament were accepted by western neighbours because they served an important strategic and political aim - binding West Germany into the alliance system.
Another political and practical reason was the emergence of European integration processes. Very early after the war, the idea of closer economic and political relationships were seen as a way of ensuring future conflict would not occur, and by co-operation European states would avoid competing with each other. On a political level, discussions began very early and the European Coal and Steel Community of 1952 was the first step in building a more integrated and peaceful Europe. The real key to this was the Franco-German relationship which soon after the war shifted from the long-standing antagonism it had been for a century towards one of friendship and co-operation. Both the French and West German governments saw this as vitally important and the Elysee Treaty in 1962 between France and Germany was an important step in reconfiguring their relationship. This Franco-German reconciliation began even during the occupation itself, as the French encouraged school exchanges between German schools in the French Zone in south-west Germany and French schools, as well as other forms of contact. [F. Roy Willis, The French in Germany, pp.177-178]
In terms of eastern neighbours, initially the Eastern Bloc and West Germany had no relationship to speak of - the Federal Republic did not recognise the GDR, nor did it accept the 1945 border shifts. It was not until the 1970s that this began to thaw - Willy Brandt's Ostpolitik saw recognition extended to East Germany, official acceptance of the post-194 5 borders and building economic relationships with Eastern states.
Another interesting aspect is West Germany's relationship with Israel - while there was no official recognition until 1965, the Federal Republic and Israel signed an agreement concerning reparations for confiscated Jewish property and for the use of slave and forced labour in 1952. The next 14 years saw West Germany pay 3 billion DM to the state of Israel, and this money was a vital source of revenue for the new Israeli state.