What is your greatest Adsense advice?

[webmastertexas]

Just wondering. What is the one thing you think is the greatest advice you can give to newcomers to Adsense on how to improve their earnings? It doesn't have to be a big secret, but something you think is a "tip" or a "hint" about how to use Adsense for maximum effect. Maybe something you did wrong, then finally figured out to correct, etc.

[swoop]

As a brand-newbie to AdSense, I really appreciate the original poster beginning this thread.

[progex]

If your layout looks cluttered, an Adsense ad with rotating background colors (obnoxious, in-your-face but easy to read colors work the best) will perform better than an ad with no background or table borders.