I have recently updated my website greenmowers.org, and would like to know how I can improve it. P.S.-My search engine placement is VERY unstable. It recently fell in rankings, but the new rankings differ in google from IE9 and Firefox (from google) .
In terms of looks, the site does look great. A few changes that I would make, is to have the nav menu aligned with the header/banner - so that they are the same height. Also, try blending the ad space in with your site more... making the background the same as your site adn try to get rid of the horizontal scrollbar. In terms of SEO, your titles and descriptions are too short, you could try putting in more information and keywords. Also, it seems that your code has quite a number of errors in it, maybe try to validate it and see if you can fix them.
You are an amazing creator, artist and an example of "You can do it if you think you can do it." I can absolutely see the passion and gut-wrenching love you have for writing about your subjects Magnificent! because there are so many who will appreciate what you do. BTW, why dont you have any meta tag or description for your site homepage ?