The key to a successful SEO campaign is knowing what words your potential customers will be searching for. Professional SEO services can provide this research as part of the deal.
As a business owner or marketing specialist, take this into consideration. If you were looking for what your firm offers, what would you type into Google or Ask.com? Are you looking for a "Lawyer in Jacksonville?" or a "Thai restaurant in Jacksonville?" You can't always know the exact words and the order they are used, but with a good general idea and some long-tail phrases thrown into the mix, potential buyers will be able to find you in just a few clicks.
Unlike most internet advertising, SEO won't deliver customers on a per-click basis. Traffic is only limited by the time investment of the link and content building campaigns, and the number of people who are looking for those particular terms.