Do you use traffic exchanges? I tend to find these produce a lot of impressions but no clicks. Simply gets your site into an exchanger but produces few clicks.
If the site is new, the chances of it displaying PSA (public service announcement) ads are very high. It'll take about 1-3 months before you can begin to see relevant ads to your site. That is why many people advise to not add AdSense until your site has aged quite a bit.