A very comprehensive WebmasterWorld thread has advertisers sharing their biggest AdSense tips and tricks. The post spans two pages, but here are some golden nuggets of wisdom:
- Medium to large rectangles outperform other ad types.
- Try to blend your ads into your website if possible because it increases CTR.
- Horizontal ads can be successful if strategically placed.
- Remove low earning pages and focus on high-earning pages for the highest eCPM.
- It helps to minimize AdSense on sites that have a lot of affiliate links.
- Put appropriate keywords around AdSense ads.
- Understand heatmaps of your site and place your ads in suitable locations.
Other tips are shared and expounded upon in the WebmasterWorld thread; feel free to join in on the discussion.