As a rule of thumb, the width of the ad sizes tend to perform better than ads that extends for more readable . Readers absorb information in the " unit of thought " , just a few words at a time . Wider size enables users to read more text at a glance without having to move the line and back to the left margin every few words as it had to be done on a narrower ad .
If placed correctly , the width of the ad sizes can significantly increase your income . Size that we think is the most effective Large Rectangle 336x280 , 300x250 Medium Rectangle , Leaderboard 728x90 , and 160x600 Wide Skyscraper . Keep in mind that although some of the ad sizes typically perform well , you should use a measure that is consistent with your page . For more information on the size of the ad , see the ad sizes . Would be better if you add the suggested ad units rather than adding two smaller ad units coexist .
Tips in maximizing ad space is minimal : Try one of the links downsized unit , as shown below . Some of this size is flexible enough to fit in locations normal ads .
Guide to ad sizes : https://support.google.com/adsense/answer/2953032?hl=en