The Placement Tips of ADS
A site visitor clicks your page and, in many cases, strength of mind about the significance of the page before he ever scrolls down or moves the page in any way.
For all intents and purposes, you have only one shot to make a good first impression: No matter what a visitor sees when that browser window loads is, for all intents and purposes, what he gets.
So, the most imperative elements of your site should be loaded into that area above the fold. Information that’s not quite as essential should be placed below the fold.
For your AdSense strategy, this means placing ads smack dab in those sections of your site where a visitor’s eye is most likely to land, which are
At or near the top of the page (either straight away above or without more ado below the title of the site, depending on how well the ads integrate in that spot)
Above the content, or at the least, imbedded in the content above the fold
On the right side of the page, blended with the other content that usually appears in the sidebar
On the left side and the bottom of a page (only efficient when the ads blend well with the other rudiments of those sections)