Even though you can also earn from CPM, Adsense is basically CPC ad network. IN order to earn well from Adsense, you should have a better click-through rate and CPC rate. You can increase your click through rate when the ads displayed on your site are useful and interesting to your visitors. This can be done by publishing SEO content because adsense is con textual advertising, which means it will try to display ads that are relevant to the niche of your website.