After the war, Germany was in a unique spot, geopolitically. As you may know, the 'core' german territory (which is waht forms modern day Germany) was divided into four sectors (Soviet, US, GB, French). Three of them later were unified to form the Federal Republic of Germany (short FRG - the former US, GB and French occupancy zone), whereas the Soviet occupied zone became a socialist state, the German Democratic Republic.

This division reflected the bloc building Western-capitalist systems vs. Eastern Communist-style systems and Germany was thus put at the very center of the Cold War. In order to guarantee that the rest of) Western) Europe would not be put under Soviet influence, like Czechoslovakia, Poland, and the the other easterb countries had, the US wanted to create a stable 'buffer' zone in The FRG and figured the best way to do so was to make sure the young Republic came back on it's feet economically rather sooner than later. The main instrument used for this was the Marshall Plan, which was a plan pushed especially by State Department employee George F Kennan to financially help out Western European countries suffering from the consequences of the war, in order to contain communist influence.

The Marshall Plan (or ERP - European Recovery Program) helped stimulate economic growth in all Western European countries and is today seen as one of the catalysts of the 'Wirtschaftswunder' ('economic miracle'), a period of enormous economic success in the FRG. By 1951, Germany had economically recovered to pre-war strength. By 1962, Germany had full employment again, (meaning less than 3% of the people abke ti work were unemployed). Industrial products such as steel, and subsequently, high quality end-consumer products such as the today closely associated german cars became major high demand export goods and contributed largely to germany's economic success from the late 1950s until the 1970s.

What helped during this time was that Konrad Adenauer, the first german Chancellor pushed a strong pro-US, pro-Western course from the start of the FRG, and thus created favorable trading conditions with not only the US itself, but also with it's allies. The joining of the NATO in 1955 solidified this state even further, even though there was heavy US military presence ever after the war in huge bases such as Ramstein, Spangdahlem, Wiesbaden, Heidelberg etc. (These bases were also bases for many international Operations of the US military during the Cold war and after, and their existence alone often was a big economic factor for the surrounding german regions).

Internationally, Western Germany profitted from a rise of free-trade agreements, as well as the formation of the European Coal and Steel Community (ECSC), which was the first trade Community of countries in western europe, and stood model for later unions, such as the European Economic Community, which was the base of todays EU.

The fact that Germany became an economic player within the ECSC as well as the EEC was precondition for it's role in today's EU, which again is the regulating and often governing force of one of the largest markets in the world.

Source: Dülffer, Jost: Europa im Ost-West-Konflikt 1945-1990, Munich 2004.

Of course, there is so much more to be looked at than what i wrote, as international relations are highly complex and played a huge role in the process if German development, but i think i covered the basis.