_ Use the appropriate colors that match your site. - Use best ads format. - position your ads. PM me for more.
To expand: Make the Adsense ads match your background so they look like any other link on your site. Use the correct shape ad, a square is good for the begining of blog posts and a skyscraper for the sidebar etc. Possition your ads between the content or under your navigation bar, this helps get the highest CTR possible.
Sometimes CTR increases if ads stand out. It really depends on the niche and takes precious experimenting..
i bought a book recently which help me a lot about boosting my adsense revenue. Anyone need it mail at . The book title is "Triple your Adsense CTR in three steps" by Jonathan Leger. you can see it in his website. - adsensegold.com
Proper ad placement and blending / contrasting the ad with the contents depending on your niche. I have success with blending!