One of the best ways I've found as I point out on one of my hubs is to find some keywords about what you are writing about that have no competition. You can do this by using Google Keywords Tool and inverting the competition row by clicking on it. You will find keywords that only get between 1-1000 clicks per month, but have no competition. If you create a hub with those keywords you will rank well in Google. You can then link your other related hubs to that one. It works great and actually gives you ideas about other topics to write about.
I got this idea from a poorly named system called Google Traffic Pump which you can check out at my hub http://hubpages.com/hub/web-traffic-how-to-get. The link is in the 'related links' section at the bottom.
But Kavitamartin12 is equally as right -- social networking. You can't be a one trick pony in this world. Good luck!