The saying "You become the average of the people you surround yourself." is a very wise piece of advice. Try to meet people with similar interests (professional or otherwise). If applicable try getting in front of a smaller crowd and talk to them about a subject that's interesting to you.

Unless you live in a very lonely, rural area (and even in those there often is at least a church community to go to) there probably are lots of local opportunities for meeting people. Meetup might be a good starting point for meeting like-minded people: http://www.meetup.com/