Just like SEO their is other service called Adsense optimization service. Hire them for your adsense optimization work Second your site should have enough traffic.
seo it and make your site an SE friendly....write a good and trendy articles then promote it... note: FB and twitter traffic are good BUT if the clickers or majority of the clickers in your adsense are coming from social networking sites google might ban your adsense account
Could be: 1) Adsense is a rip off 2) you don't know what you're doing (ad placement, ect) 3) maybe both