Amit Agarwal from Digital Inspiration has compiled a list of his favorite and most productive AdSense tips. A total of 26 tips are included. Besides warning that publishers should adhere strictly to AdSense policies, I'll highlight a few here.

• Don't start another "student consolidation" or "home equity loan rates" website. It will never make money. Instead, write on what you are passionate about. Don't waste your money on high-paying AdSense keywords lists.
  
  
• For short articles, CTR is best when ads are placed just above the content.
  
  
• For long articles, CTR improves if ads are placed somewhere in middle of the content.
  
  
• The ad border color and background color should be same as the page background color.
  
  
• Always put ads above the main fold.
  
  
• The large rectangle is definitely the best paying AdSense format (336x280).
  
  
• Eliminate the ad link URL by setting its color same as your page background color. (This is one I have never even thought about)

Those are just a few of many more tips that will help you to get the most out of AdSense.