Increase Earning by placing right ad Unit.
Right Ad Unit? Means?
Yes, Right Ad unit here means an ad unit whose impression CTR and Ad Request CTR is high.
Every ad we place in an article not earns same. Some earn less, some more. Our team experiment on 10 adsense accounts, for different ad units. And finally found that Different Ad Unit at same area/place of a webpage.
Then you may see changes in CTR, CPC, RPM.
And if you check the report of your ad units, then ad unit that earns max will get high CPC and earnings. Now there may be a question why is it so? It is all because of High Ad Request CTR, unit you placed has high CTR that mean Impression vs Click rate is high, More ads served to that ad unit than other ad units of the page.
A lot of factor plays role in this, such as the number of ads on a page. I recommend, less ad with high CTR would be a great idea.