Adsense is putting up ads based on the content of the page. So have a look at the ads that are being generated on your pages. Are they pertinent to your audience? Is your audience the type who click through on ads? If the ads are inappropriate for the page, then you can tag the intended content that the ads should relate to. Using an appropriate file name can help as well.  Forums can help too, if the discussions are about subjects that bring up worthy ads.

Also have a look at the placement of the ads. Are they buried where they are less likely to be noticed? The adsense game is a bit of an art. You do not want the ads to overwhelm your site, but they need to be highly visible in order to attract clicks. Strike the right balance and you will see better results.