The following is the beginning of an article on Google’s Webmaster Central Blog called “More guidance on building high-quality sites“
“In recent months we’ve been especially focused on helping people find high-quality sites in Google’s search results. The “Panda” algorithm change has improved rankings for a large number of high-quality websites, so most of you reading have nothing to be concerned about. However, for the sites that may have been affected by Panda we wanted to provide additional guidance on how Google searches for high-quality sites.
Our advice for publishers continues to be to focus on delivering the best possible user experience on your websites and not to focus too much on what they think are Google’s current ranking algorithms or signals.”
The article mentions 23 things you can do to improve the quality of your website.