How many social networking sites are you a member of? There are already tons of social networking sites out there and as of this writing a couple more people are probably developing more.
One way to generate traffic is to join one or maybe a couple of these social networking sites, add a lot of contacts / friends, and then promote your web site to them. If you have a good relationship with your friends/contacts, more likely than not, they will pay your site a visit. Each visit is a valid traffic to your website. The more traffic you have the higher chances you'll have of earning from your Google Adsense.
Remember though that writing good content is of the utmost importance. Your friends and contacts will only come back to your site if they find value in your web site. In order to get consistent results, you need regular traffic and not just one time visits.
Avoid abusing this medium as well. More likely than not, you have common friends / contacts in different social networking sites. Posting the same articles on all your networking sites can piss your friends and readers off. Shameless self promotion is a horrible long term internet marketing strategy.