When we are working with a web site to help increase their natural search engine ranking for sites like Google, we are often asked, "How many keywords should we be tracking?"
We usually encourage people to break down their list into at least two, and sometimes three groups:
Optimize your primary and secondary keyword pages first. Wait for your rankings to improve--then go in and optimize for the tertiary keywords. They're easier to rank for and will convert better, but don't get as much search volume.
Choosing the right keywords is just one element for implementing an effective search engine marketing campaign – and when you do so, be sure to optimize your pages, and spend some time building links back to your pages from other sites. A little attention to this matter can be greatly rewarded with increased, quality traffic to your website.