I am a member of a local chamber for 4 years and a BNI group for the past 14 years.  I have found that being part of a networking group has allowed me to expand my knowledge of other types of services, adding to my credibility with others by referring individuals to businesses that can help them outside of my own business.  In BNI they call it Givers Gain but I call if living by the golden rule of helping others.

All networking groups help you grow personally and business wise by being able to learn better public speaking techniques, polish your presentations and learn better people skills.

The most important aspect of networking groups is learning how to LISTEN before speaking and put others first.  Introduce yourself but listen to others, ask questions of them and make them know they are the important person in the conversation.  Be the person others trust and want to build relationships with and you will indirectly build your business strong.  I try to remember that Trust is what strong foundations are built on.