Some publishers believe that increasing the visitor traffic is the only sure-fire way to increase ad revenue from their blogs or websites. While increased traffic generally does mean more ad revenue, the publishers are still leaving a lot of potential ad money on the table.
and where exactly? Simple, the CTR.
I’ve written a blog post about the Top 5 elements you can tweak to increase your ad earnings. While ad placement is a natural and obvious winner, the most surprising thing which works pretty well is Ad design and type. Just by playing with the ad colors and types (Image vs Text vs RM), you can get a considerable increase in your unit’s CTR.
Has anyone here focused extensively on optimizing CTR? Would really like to know what worked for you and if you have any case studies to share 
Thanks,
Ankit