Aaron Wall, popular author of SEO Book Keyword Suggestion Tool, shares two simple but very effective tricks for websites that show Adsense Units:

Tip 1 : Adsense Website Layout
A page width set to 100% gives the ads a relatively small % of the screen width. Aaron suggests that it makes more sense to set a page width and center the page layout. 760px is a recommended page width.

Tip 2: Adsense Website Fonts
This is again necessary for a perfect blend - Match your text size and Font with that of Adsense Ads. This information can be derived by looking at the HTML source of Adsense Ads.

Read: AdSense 101 Tip: Controlling Page Width