Every Project or every product need to have "raw materials" to build an end-product and these raw materials form the solid foundation for any product or project to come into existence and even survive with minimum disorderness or entropy.

Likewise in SEO to optimise any site to optimize for search engines the very first thing that need to be researched thoroughly is - Keyword Research.

While doing keywords research, points to ponder and things to keep in mind -

• Relevancy to theme of website (as it would attract relevant visitors to a site and visitors dont even know of every site on web so they obviously put search terms that queried in their minds)
• Inculcate as many keywords as possible - Remember keyword research is an ongoing process till life of any website.
• Research the competing sites and their meta tags keywords as you would save time by having pre researched material.
• Use keyword suggestion tools -

Overture suggestion tool -

http://inventory.uk.overture.com/d/searchinventory/suggestion/

http://www.keywordhere.com/

Google Keyword tools -

https://adwords.google.com/select/KeywordToolExternal - This tool has an site-related keywords fetching function which brings keywords used/ linked for that site.