The use of aisatsu is probably one of the best ways to strike up a relationship in Japan. "Aistatsu" are greetings such as "Konnichi wa" (Hello, used during the day). Try using aisatsu at a variety of places; eg. in the elevator, in the park, at ths supermarket or in the izakaya (as per the above entry). Japanese love to see foreigners trying to communicate in their language. While not every "aisatsu" will lead to a friendship, they are one of the best ways of starting one, and not when you are just new to Japan either!