There is a lot of advice on networking and even courses on how to do it. My thought is you first need to find the right group for you, each one is different even within the different franchises. Any group will be defined not only by it's structure but also by it's members. So go out and find one that works for you, one that meets at the right time of day, with the right frequency. A group that has the right structure for you and your needs, but mostly a group with people you can talk to and feel easy to network with.
Once you have found your group stick with it, be " a good member" one who turns up as often as they can, one who contributes, someone who listens as well as shares. If you develop your relationships referals will come naturally from people confident in you and your services.