When you display an Ad in the same location with the same colors and Ad format, regular visitors tend to ignore them. This is called Ad Blindness.
The tip here is to rotate between four different color palettes for your AdSense Ads.
1. Log in to your account at https://www.google.com/adsense
2. Click the AdSense Setup tab and choose AdSense for content as the product
3. Choose an Ad type and format.
4. In the Colors drop-down box, click “Use multiple palettes”, then select up to 4 color palettes by holding down the Control or Command key
5. Copy-and-paste the AdSense Ad code into web pages
As 4 different color schemes are used randomly on your page, there is a good chance that your visitors will click the Ad thereby increasing your click through rate (CTR) and allowing you earn more with AdSense.