Google Adsense is no doubt, the best cotextual ads network for publishers. If you still haven't read my guide to get approved on AdSense in less than 72hours , then I will recommend you do.
There are several techniques or ad placements that determine how much you earn with adsense. Here is a well illustrated infographic showing you how to earn more with Google Adsense.

Source: WhoIsHostingThis.com
There are several techniques or ad placements that determine how much you earn with adsense. Here is a well illustrated infographic showing you how to earn more with Google Adsense.
Source: WhoIsHostingThis.com