Hi There,
Google has just released a starter guide mapping out all of the basics along with new sections covering mobile search.
You can download this free guide from here:
http://www.google.com/webmasters/docs/search-engine-optimization-starter-guide.pdf
The guide covers all the usual stuff like Meta tage and Alt Tags but is really easy to read and digest. If you just followed this guide and did nothing more your site would improve its ranking in all search engines.