I started doing 100% better (literally) after adding fully fledged mobile versions to all my xxx sites (Mech Bunny, KVS, Wordpress, for the most part).
The combination that I am using right now is
Bitter Strawberry +
Sex Goes Mobile (two at the same time, or ad rotation) + mobile popunders from
Plugrush. This is a very good way to double your income, in no time (as long as you get familiar with what these companies offer on their sites).
For high traffic websites, you can try to mix in
First Mobile Cash, and
VPS Mobile, but this is somehow more advanced (in general, they may be somehow more profitable than the regular mix <above>).
I knew about mobile, but I did not realize it, in a way. Again, I made sure I have top notch mobile versions of my websites, and I am making around 80% (up to full 100% sometimes), with these sites.