How to start a good friendship in America?

I'm not from the U.S. and will be spending the winter there. I'd love to make American friends but tend to refrain due to past experiences in Europe, where people focused more on long-term friendships. For instance, in Germany, I didn't make friends because people seemed less open, but in New Zealand, I made great friends. What should I expect in America? How do people usually make new friends? All in all, making friends varies by country, and I'm open to taking the initiative.