For instance: like for like events. Do I participate in these? Yes, I do. For those not in the know, these events are usually huge, having at least several hundred participants, on average. Authors tend to throw them under the guise of ultimately helping other indies promote their work. The real goal, however... The quantity of your fans. Not having more active fans who are genuinely interested and enjoy interacting with your page, but to have that # of likes simply be as high as possible. In theory, more fans means more exposure, and greater chance of someone purchasing your book.
In practice, however, the number of fans doesn't much matter. I just hit 1000 fans on my page, and I haven't even sold 10 copies of my most recent release yet. I also advertise on Twitter. I have a fairly active, engaging fanpage, but the quality of fans seems to be more important than quantity alone. So while networking with other authors is indeed fantastic, you've got to have more to it than that. I'm doing a review only blog tour soon through Nevermore PR, and if that goes well, then I might branch out into a bigger tour with interviews and whatnot.