I believe many AdSense publishers heard that fewer ads per page may bring high CPC resulting in more earnings as people will click on the high competitive ads? Though this may be true, actually fewer ads mean less options for people to click on ads - lower CTR. In addition, there is a well-known theory of putting ads above the fold for getting the attention of readers. Dos these theories work for you? How many ads per page you put. Have you tried more ads? And what about ads down the scroll?
Adsense will show the most relevant and high paying ads first. So if you have a lot of adsense blocks you will be showing lower paying ads.
I have learned that lot of adsense blocks get more clicks (it is like an intensive to click on ads) - no matter how many ads you have, you just have more clicks when having more ads.
The secret is just to place ads on best places where people see them, I guarantee you that your CTR will get higher with smart placing instead of filling a page with ads. Most visitors with some sense in their minds see that your only after the money and clicks and probably leaves the page earlier than planned. It has to look "natural"
One ad block above the fold (336x280 large rectangle) at the top of your content seems to get the most clicks and highest CPC for the reasons already listed.
Occasionally, I've gotten good results off of the (160x600 vertical) and once off the (468x60 banner). The key is to always test... test... test... because not all sites are the same.
I've seen better results with 3 ads (300 x 250 at top, 468 x 15 link at top, and 160 x 90 link unit in sidebar). With this I make around $4.00/day from the site that it's on, which is twice what I was shooting for. Quick question though, when searching for a niche, I feel like I should also take into consideration the local exact search count as well as monthly average. Would anyone agree? Cuz I have a site a pushed to #2 in search results that supposedly has 5400 searches per month for the keyword, but so far no visits lol. Could it just be out of season right now?