First, sorry for my bad English, I'm Spanish.

I offer my experience (not much) with Adsense. Certainly many (if not all) of these tips, you shall know but I would like to share.

Tip 1.
Putting AdSense on the top of the website. I personally have not had luck with Adsense in the sidebar or at the end of the content. My experience tells me that where they yield more ads is the beginning of the post, just below the title and content before.

Tip 2.
Do not give many options to visitors. If for example, when you enter in the website, just option click on an advertisement and not a category or another link, gives more performance. Most users are lazy to use the scroll bar of browsers.

Tip 3.
The best colors. To me the best color for ads is blue for links #0000FF, white background color #FFFFFF and black for the text and the URL of the ad #000000.

Tip 4.
Pages with few links, more clicks than others with more links. For example, in blogs where posts are not showing the categories, these had a higher CTR.

Tip 5.
Do not put pictures in posts. On blogs where there are no pictures in posts, these have higher CTR.

Tip 6.
Less ad units, higher eCPM but lower CTR. It is true that if you put only one ad are better paid, but also the CTR is much less.

And these are some of the advice I can give in my experience with AdSense. I hope you find them useful.

Thanks,
Sergio.