An effective means of networking is to find business associations and chambers to join. For this to really become effective, however, you cannot just belong.
With any group, club or organization, you need to not all join up, but then get involved. Become an officer. Serve on a committee. Contribute your expertise. Invest some time. Make your presence known.
Here is a test to determine whether or not you are sufficiently involved with any organizations you are associated: If you were not there, would you be missed? If not, you are not sufficiently involved. Set about changing that the first chance you get.