Excerpt from: Don’t Waste Time on Google AdSense
You should place Google ads on your webpage in a manner that gets prominent exposure for the ads but does not harm the user experience. While you want to maximize your Google AdSense revenue, you don’t want to offend your site users with too many ads or ads that obstruct your content.
Placement of Google ads on a webpage is an art and a science. A great deal of study has been given to what type of ad positioning leads to the best results. Naturally, you can get attention for your Google ads by placing them high on your webpage, mixing ads into your content, and using bright colors for your ads. The problem is, users become offended quickly by overbearing ads and are more likely to leave your website without viewing your content or clicking on your ads.
Before deciding where to place Google ads on your webpage, you need to make sure your website content is logically laid out and your site is easy to navigate. Successful advertising starts with successful content. So make sure you maintain a useful and comfortable user experience throughout your website.
Once your website content is laid out with the user experience in mind, choose ad colors and fonts that coordinate well with your website. Although you never want to confuse anyone as to what is content and what is advertising, it’s good to maintain style coordination between your ads and your content to enhance the user experience. Choose prominent colors for your ad headlines and make sure the description lines are legible.
Place vertical ad units immediately to the right or left of your content. You don’t want the ads too close to your content so as to interfere, but close enough for your users to easily see them. Consider placing a horizontal ad unit right at the bottom of your content, as users often want to be led to their next destination after finishing a piece of content. You can also place horizontal ad units in the middle of your content, but be careful not to obstruct your content to the extent that you offend your users.
You’ll also want to be careful about placing too many ads on your website. Google allows you to place 3 ad units, 3 link units, and 2 search boxes on each page of your site, but you need to make sure you’re not overloading your site with ads; otherwise, your users will view you as a spammer and ignore your site altogether.
See: What makes people instantly click Google Ads now?
Avoid common pitfalls and make money with Google AdSense by reading Don’t Waste Time on Google AdSense.