I really believe that you only can increase your ad click rate with a lot of traffic, maybe with a plain layout and with few internal links, I have two web sites, and I am geting a lot of click in one because the template is very simple with few internal links, and the other web site is getting more page views but lest clicks, but anyway you will not make really money with adsense if you don't have a LOT of traffic to your web site...