In addition to Adsense, consider affiliate programs. Also, if you have content on different topics it might boost your earnings as the cost per click might be higher. Furthermore, consider optimizing the placements of your ads.

Hope that helps. Good luck!

adsense cpc are based on keywords used at the page. If you want to increase your earnings you should get into market with high cpc. (High paying keywords)

There is no alternative of adsense in best of my knowledge. Many are out there but you will get very less amount as compared to adsense.