Comming back to the topic about how to optimize adsense
The two AdSense secrets to choosing the right ad formats for your content pages are:
Design your ad to stand out without disturbing the layout - Best ad fits into current webpage layout instead of disturbing its flow. Google offers many ad formats suitable for different part of your webpage. For example, if you want to fit the ad into your navigation bar, then you can choose AdLinks units or many of the vertical ads.
The secret is to always blend the format in. Imagine using a rectangle ads on a narrow navigation bar. It will make page looks ugly and unprofessional. The last thing you want to happen is losing your credibility because of amateurish website.
Format it to look like part of your webpage naturally - People have developed what marketers called ad blindness online. There are very little value to push ads (that look really like ads) to website visitors. Other than the awfully low CTR, which just a waste of your webpage real estate, it actually can ruin your website as authority.
Avoid unnecessary distraction and lead your visitors to your most wanted response. Ugly advertisement turns them off