Here is a really interesting post from the official Google blog.
It goes into some detail about some of the user testing and eye tracking Google are doing. The post looks at some of the differences that have occurred since Google introduced universal search into its search results.
Also, if you look at the search results heatmap you can see how important the top two entries are in Google’s search results. Also, you can definitely understand why Google puts more and more sponsored results above the search results as well as to the right. It must be ever so tempting for them to lessen their quality guidelines to allow more and more ads to make their way to this sweetest of spots.
Lastly, if you don’t already, this is a good time to branch out into picture and video search engine optimisation. You are missing a big win here and you definitely are if any of the search terms you would like to be listed for have an inherent visual element (just like ‘how to tie a tie’).
P.S. if you want to do some of your own (not eye but mouse pointer) heatmaps and user tracking, visit ClickTale. They have a fantastic tool that allows you to see a Flash movie of how your visitors have interacted with your site (what they click on, how long they spend on the page, where their mouse goes, etc.). The entry version is free and I would highly recommend having a look.