Using your favorite search engine to do a web search for "Joomla SEO" will help you on your way when you want to know more about optimization techniques. If you want to delve a little deeper into the principles of SEO for your website, make sure to have a look at the Google starter guide on SEO (http://www.google.com/webmasters/docs/search-engine-optimization-starter-guide.pdf).
You might also want to have a look at these sites:
SEO tips for Joomla on the JoomlaBlogger site: http://www.joomlablogger.net/seo.
The Joomla community magazine on SEO: http://magazine.joomla.org/issues/issue-feb-2012/item/675-5-great-SEO-Resources-Be-Your-Very-Own-SEO-Expert-for-Free.
Browse the SEO and Metadata and SEF categories of the Joomla extensions directory (http://extensions.joomla.org) to get an idea of the many extensions available to assist you in optimizing your site's search engine visibility.