In "real life" (offline) a good deal of networking comes via my job. I meet a lot of people, get to know folks, and have had occasional work or offers come my way thanks to it.
Online I just find communities I like and participate. That's it. Be fun, be friendly, be a part of the community, and sometimes good things come your way. People get to know you, maybe (hopefully!) they recognize your talents, and maybe they reach out to you with a job or offer, or can connect you with someone who has one. I've had a few decent gigs come my way by that route.
I don't get exceedingly active in marketing myself, but that's largely because it's too easy to spend all day doing that and no time actually WORKING. So I stick with the fun stuff - doing it for the fun, not for what might come of it - hope for the best, and spend the rest of my personal time trying to be productive.