SEO Copywriting is a combination of art (the words) and science (the math) resulting in website copy which produces actual, not perceived results. Knowing the "math" and "structure" preferred by the search engines is the first component to successful SEO copywriting.
Knowing what keywords your audience is searching for, and which keywords are making your competition succeed is crucial. Forget about what YOU think -- it doesn't matter and no one cares! Use a comprehensive analysis tool like Web CEO http://www.webceo.com/cgi-bin/go/clickthru.cgi'id=chrisconl to strategize and track your results.
Divide your keywords up into three tiers, write them out in three separate columns if you have to and see which individual words "piggyback" on each other. Follow the searcher's behavior, combine terms, go against the grain when copywriting for SEO.
For example: You want visitors seeking "Google Page Rank"
You begin the process:
(1) Keyword Research
(Keyword Set, # of Daily Searches,Competition - # of indexed pages)
Google Page Rank, Article Source: The FREE Article Distribution Center