I'm not a super experienced networker, but how I've tried to do it (which has been summed up by previous posts) is basically to make friends at 20SB, keep up with their blogs, comment, interact on Twitter, etc. The nice thing is that very, very quickly, it's not about networking but about friendships. Pretty sweet deal, I think. :)
I haven't purposely tried to network my blog, mostly because I write for the love of writing, not necessarily for a high number of blog readers. I joined 20-sb mostly out of curiousity because I saw the badge on a lot of blogs I enjoyed-- and it has allowed me to find even more great blogs, and consequently people have found mine. I still don't have a whole lot of regular visitors, but I cherish the ones that I do have and the comments they leave. Similarily, I have became regular readers of their blogs, and I'm trying to be better at commenting and de-lurking myself.
In addition to all of the advice here, I'd like to through NaBloPoMo into the mix. NaBloPoMo stands for National Blog Posting Month. They have themed challenges all year long, but November is the big one. I signed up for that soon after I started my blog and I found a lot of great bloggers through it.