It can be difficult to find new friends when you are an independent working adult. The orientations and ice breakers you experienced at school are no longer available to you. But instead of sitting at home and avoiding communication with other people, learn to develop interests and find others who like the same activities.
Join a Club or Group
Many groups and clubs exist in any location and can easily be found online. Sites like Craigslist and Meetup offer a large database of groups ranging in activities from book clubs to pick-up basketball to crochet classes. Generally there is little or no cost to join. Since these are groups welcoming new members, they offer less pressure than approaching random people in public.
Enroll in a Class
Learn more about a favorite subject, or finally get to know how to fix a car by enrolling in a course at a local community college. Don't expect to pay more than a few hundred dollars, and sometimes much less, for a semester. You will find plenty of new students to meet at the college. You can join a study group or go out for coffee after class. Community college classes are often offered at night, so they do not conflict with traditional work hours.
Attend Work Functions
Many people want to head straight home after a long day at work but a good way to get to know people is to go out with coworkers for a drink or dinner after work. You will automatically relate to your coworkers since you all work at the same place. Not only will time after work get more fun, but you could also develop friendships useful during office hours as well.
Getting out of the same city, or even country, for a while can be liberating and help you meet new people. Relationships you make when traveling are likely to be short term since travelers tend to go their own ways after a few days. So this is an opportunity to try breaking out of your shell, approaching new people and practicing developing relationships. And when you return you will have many stories about the trip you can share with others as ice-breakers.