Once you’ve settled in to your daily routine and sized up the people at your workplace, don’t limit yourself to hanging out only with the people you already know. Get in touch with every friend of a friend whose email address you have been given, and when you think you may have come upon other Americans (or, choose your nationality), don’t hesitate to say hello.
When you overhear people who are obviously American (or, choose your nationality) talking on the subway or in a queue, wait until the appropriate moment and introduce yourself. You'll probably be surprised to find how happy people are to find compatriots when they are traveling. Don't miss out on some of the richest experiences you may have by hesitating to speak up and introduce yourself. Make an effort to find new friends to share the ups and downs of expat life.