To get the best income from Ads when using Adsense ( or any other Ad serving programs) you must regularly monitor which ad units are getting the best CTR ( Click Through Rate) and also monitor which ads are earning you the most per click. With these two pieces of information you can make sure that you are getting the best from your Ads.
People sometimes think that Adsense automatically matches the best paying Ads to the Ad unit on your page which has the best CTR. You may be surprised to hear that this isn't the case. lets see why this might be important by looking at an example.
Consider a web page which has two ad blocks. A and B. Ad block A comes first in the HTML of this web page - so Adsense delivers the best paying ads to this Ad unit and lower paying ads to Ad unit B. Lets imagine that Ad Unit A is a banner ad unit at the top of the page and Ad unit B is an ad unit at the bottom of a post. So far so good then eh?
Hmm. What if Ad unit B actually has a better CTR than Ad unit A? If you think about it this is a real problem. What you want is that the best paying ads are shown in the ad unit that gets the best CTR - but this is not what happens!
Because Ad unit A comes first in the page HTML code Adsense will serve the best paying Ads to that ad unit - so you could be losing out on significant ad revenue!
So that's the problem - what is the solution?
What you need to do is to ensure that the Ad Unit with the best CTR is the first one that appears in the actual source code of your page. If your ads are placed inside
<div>elements then you can make sure that this ad block appears first in your ad code but then use CSS positioning for example to make sure that when the ad displays it appears in the position that you want.
This is a really important tip to get the best of your AdSense so if you want to maximise your income from AdSense using this tip then you must understand CSS positioning.