Use Text Ads instead of Image Ads as users get more options. If you still want to display image ads, consider ad formats that support image ads - Choose either the 300×250 medium rectangle or the 160×600 wide skyscraper - or both, if you display multiple ad units on a page.
Google Ads without background color and borders always perform better. Make the border color and background color same as your page background color.
Always put ads above the main fold. Make sure that the ad unit with the highest clickthrough rate is the first instance of the ad code that appears in the HTML. Since the first ad unit is always filled before the rest, you want to make sure that ad unit is located in the best placement on your page.
Try setting the ad link URL color to a lighter shade. If your text is black, you may make the adlink as light gray.
Go Wide - The large rectangle is the best paying adsense format (336×280) - The Google Adsense Publisher team also feels that the best formats are the wider ones - the ad formats that contain the widest individual ads. Try using the 336×280 large rectangle, 300×250 medium rectangle, or 160×600 wide skyscraper.
. Placing images next to ads or above ads does help in attracting user attention.
Blend AdLinks with other navigation links or place horizontal adlinks at the top of your webpage. AdSense publishers are permitted to click on link unit topics on their web pages, provided that they do not click on any Google ads on the resulting page.
You can put upto 3 adsense units on a page. Try putting a large skyscraper on the right navigation sidebar of your website. That area is close to the browser scrollbar. You can also add 2 AdSense for search boxes, 3 adlink units.
The first few lines of your content are an important factor for determining what Ads are served on your webpage. That’s the right place to put keywords in bold (strong or <b> tags) or header tags (h1, h2, etc).