I am using google adsense on a few of my sites and I have learned a thing or two about how to make a decent amount from it:

• Blending in is key: This is a widely cited tip but it is worth repeating. It is important that your adsense ads blend in with the rest of your site. Among the things you can do are:
  • Make the ad border colour the same as the page background colour. This way the ad doesn’t appear as a separate block but as part of your content.
  • The links in the ad should have the same colour as the links on your site.
  • Similarly the ad background and text colour should match those of your site
• Less is more: Google allows you to place multiple ad units on a single page but it is best if you stick to just one. This is because if there is just one ad unit Google will place the highest paying ads in it. This will improve your earnings per click or CPC.
• Location, Location, Location: Since you have just one ad unit to work with you should place it very carefully. The best way to do this is to wrap your content around your ad unit. I also find that positioning your ads in the middle of your webpage draws the most eyeballs and clicks.

I am still learning but I find that these steps help me earn more.