SEO methods can be classified into 2 major categories:
white hat SEO, methods that search engines recommend as part of, good content, good design and well struture. White hats tend to improve (Search engine results page) SERP that last a long time.
Black hat SEO, methods that not approve by search engine, such as link farm, content farm, hidden text.
Black hats is more hoping on instant result with minimum effort to boot up SERP. Their sites may eventually be banned either permanently or temporarily once the search engines discover their activity.
Infographic by the Pay Per Click Blog
For some time now, we have been searching for a good beginner’s guide to SEO. Forum members often post questions like ‘how or where to start SEO’? There are many sites that provide information or tutorials on SEO, but which are the best? Following the wrong guide can be damaging to a site, thus we have come up with a list of recommended references.
Learning Resources: Step by Step Guide to Start SEO
Top Webmaster Forums: SEO Questions & Answers