Improving on page content as well as considering off page ranking factors (such as quality inbound links from authority sites) in order to appear in a higher position in the search engine results is known as SEO.
As search engines have become more advanced the most important question good SEOs ask is whether the target page deserves to rank for that term. If not then significant work must be undertaken to improve the content and on-page ranking factors (having suitable titles, content, images, links to resources etc).
Once this is achieved a business must work to achieve optimal off page ranking factors. This requires exposing excellent content to those who would provide links – bloggers in the same niche may wish to review an exciting new product in exchange for their free sample (this is common in the technology field). Various other techniques such as link bait (writing content or designing tools that are so good they catch people’s attention and they share/link them almost in a viral manner) and social marketing are also used to increase the exposure of the target pages.
Some other techniques often considered ‘black hat’ include attempts to ‘game’ the search engine system by building links in less natural ways. Posting thousands of comments in forums and on blogs as well as articles in thousands of article directories often re-spun and in poor English is often seen as a strategy for gaining links. Whilst this and other methods do garner some success it is debatable whether they are a solid long term strategy for any business.