I've freelanced successfully for a few years and never really had to explicitly network to get clients. They all came from my existing professional network (built up over a 10+ year career in traditional employment). I know that's not possible for everyone and I didn't come here to say just that.

Lately I've been focusing more on bootstrapping a startup and using freelancing as a part-time way to pay the bills, so time to go out and find jobs has been less. Fortunately, I was able to connect with another freelancer who is great at networking and often lands more jobs than he can handle. He then sends work my way. I charge my usual hourly rate and I suspect he's quoting these clients with project-based billing and in some cases making a tidy profit. I'm absolutely fine with this - he takes the risk, communication overhead, blame if stuff hits the fan, and I get some steady side-income where I essentially report to another developer who is an understanding person.

Perhaps if you're an introvert, seek out an extrovert freelancer that could use some extra bandwidth.