ON-SITE SEARCH ENGINE OPTIMIZATION
On-site SEO is the most common Search Engine Optimization technique out there. A well optimized website will rank very well in search engines, and search engine rankings archieved through on-site SEO are in general very stable in their position, with the trend to move up in the ranks as the site ages.
The term on-site SEO stands for optimizing the html code and content of an existing web page to be optimized for certain keywords or search terms. It is basically a one time job, as there is only so much you can do to make the website or page "perfect".
When optimizing a web page, it is absolutely critical to have previously done the proper keyword research, as it can only rank in top positions for a limited number of search terms. Just switching two words of a search term can make the difference between getting a few and a lot of visitors.
Being one of the most common SEO techniques has the advantage of a one time cost and relative stable ranking in search engines, but if there is a lot of competition for the search term you want to rank high for in the search engines, On-site SEO may not be enough to get on top of them all and you may want to have a look at
Off-site SEO.