SEO or seach engine optimization is basically involve two things:

1) On site SEO

- this includes your website description, keywords density, website load speed and etc

2) Off site SEO

- creating backlinks, link building, social shares and etc

Hope this helps

Here's a Search Engine Optimization primer by an SEO authority, teaching more conservative methods.

http://www.seomoz.org/beginners-guide-to...

Search engine optimization is a methodology of strategies, techniques and tactics used to increase the amount of visitors to a website by obtaining a high-ranking placement in the search results page of a search engine (SERP) -- including Google, Bing, Yahoo and other search engines.

SEO helps to ensure that a site is accessible to a search engine and improves the chances that the site will be found by the search engine.

there are no any idea work in SEO. doe original content as well as high quality back link best for SEO.

SEO helps to ensure that a site is accessible to a search engine and improves the chances that the site will be found by the search engine.