I agree with you ,well there are many techniques to increase the CTR mainly those include better ad placement color and unit style and the optimal amount of links on a page,blending of ads colour with the web back ground colour and placement within post so that visitors never know that it is a ad.Another thing is content management ,good interesting topic so that you will get returning visitors and they may click your ads when they find interesting topic related ads.Place leader board and banner units are for page headers and footers and square rectangle ads with no border in side contents,just feel yourself as visitors and decide which is appropriate.