Google's page of AdSense optimization tips have been revised, so check them out. You might also want to read my own set of Google AdSense tips, which rank just behind Google's own pages when you search for “AdSense tips”.
Eric Giguere is the author of Make Easy Money with Google, a real (printed!) introductory AdSense book for non-technical people, available at all fine bookstores. Be sure to download the free sample chapter for more information about the book. Or add it directly to your Amazon shopping cart!