Ranking your keywords in SEO is not an easy task, yet many people think they can do it all themselves, with the aid of basic online tools to track keyword ranks and analytics details.
It is not actually that easy to perform good SEO yourself, as there are a lot of tools which are not easily accessible to the everyday person. SEO agencies are able to perform really in depth SEO to help you getting your keywords ranking higher on Google and other search engines. The majority of SEO agencies focus around Google because they are the leading name in search engines, and tend to have the most of the online audience, although depending on your industry you might choose to focus on yahoo or bing.
SEO agencies often charge for their SEO services as a monthly fee, rather than as one lump sum. SEO is best performed over a long period of time, as it is unusual to see any meaningful results in less than 6 months.