Ad-blindness is a condition where a site visitor whether consciously or subconsciously ignore ads placed in a site. This can be caused by several factors, such as familiar and predictable ad placement spots.
There are few techniques that you can apply to reduce this effect to help you get more clicks from your Google AdSense program, though this can be applied to any other advertisement or Pay per Click (PPC) program you're running on your site.
Website's visitors normally just focus on the content of the site (while trying not to look at the ads), and so blending your AdSense ad units with the layout and color of your site normally produce more clicks. It's not to trick your visitors to think that the ads are your site's content, but just so it gets read.
Your site's elements such as images, widgets or videos normally attracts your visitor's attention. Placing your ad unit close to them would get some of the attention. Be careful not to violate Google AdSense term of service though.
When a visitor is used to your website's layout and your AdSense units placement, they'll go straight to your site's content and skipping the ads whenever they visit your website. Having a fresh layout or maybe just a different placement for your ads once in a while would be a good thing.
Just as having a new site and ad placement layout, changing the color of your ad units would give the same effect.
Having too much AdSense ad units in a page would make your visitor to be more careful of ads. Try reducing the number and your site wold feel more ad-neutral and visitors would have more focus on your remaining ad units.