There are many tool to which a Webmaster can refer to manage their site.
Here are some of them:
Google Webmaster Help Center (http://groups.google.com/group/Google_Webmaster_Help);
Google Webmaster Help Center: with in-depth documentation on topics for Webmasters (www.google.com/support/webmasters);
Google Webmaster Central Blog: Frequent posts from Googlers on how to improve the site (http://googlewebmastercentral.blogspot.com);
Google Webmaster Tools: we optimize the way Google interacts with our site (www.google.com/webmasters/tools);
Google Webmaster Guidelines: indications regarding design, content, technical aspects relating to quality (www.google.com/support/webmasters/bin/answer.py?answer=35769);
Google Analytics: it indicates our visitors, which pages they visit and we keep an eye on the reference samples of our sector (www.google.com/analytics);
Google Website Optimizer: We optimize our pages to understand what works and what doesn't (www.google.com/websiteoptimizer);
Tips on how to use a Seo-Search Engine Optimizer: (www.google.com/support/webmasters/bin/answer.py?answer=35291);
Another useful tip I can give you and follow the channel video by Google on Youtube www.youtube.com/user/GoogleSpain, contains very useful information on the use of its services.