So as I’ve grown in this industry, I’ve found it helpful to use the Adsense Competitive Ad Filter and reduce the sites that tend not to pay so well, which drops my eCPM. For a while, I was maintaining this list on my own. Until recently, I happened upon this blog that carries a nice list of sites you should have in your Ad Filter. I’ve tried it for a while now and its helped out my sites slightly. I would suggest trying it out briefly with the list in your Ad-Filter, then for a time without and see what works best for you. Every niche works a little differently.