If you are working on getting your site to be ranked higher among the Google organic search results through the application of Search Engine Optimization (SEO), you would probably had gone through the process of keyword research. Basically you would have compiled a list of keywords with the help of a keyword tool, either FREE or commercial services. Should a potential consumer had a need and happened to search major search engines with the keywords you had selected, you site would be shown in the result page and a chance for the visitor to be directed to your landing page.
I used to do my keyword research by finding which keywords had the highest volume of searches in major search engines using a keyword tool. Should a certain keyword had searches over a pre-determined criteria, it would be added into my keywords list. These keywords would later be used to optmise my site by adding them into the title tag, meta tag and contents. This is the technique I am using until I came across a book "15 Steps to SEO Success" written by Stephen Woessner, an SEO expert in the US, who offered a different method of keyword research which made more sense.
Instead of casting a wide net hoping that I can capture a portion of market share of those highly searched keywords, Stephen Woessner offered a totally different approach in doing keyword research. He would first brainstormed a list of 10 keywords for a site, and qualified each keyword using a target ratio, which is defined as the total number of sites returned in the result pages divided by the number of monthly searches for that keyword (with the help of a keyword tool). The lower the target ratio, the higher would be the potential of that keyword, as that would means lower competition and higher monthly searches. He would select the 2 keywords with the lowest target ratio and used them to optimise his site. In that way, his efforts of optimization would be more focused, and thus better rankings should visitors search for his 2 selected keywords.
You might be thinking that researching on 10 keywords per site might sound tedious. If you had 10 pages in your site, you would need to researh on the statistics of a total 10x10=100 keywords! But that is basically what research is all about, and a lot of hard work is needed. You might want to start off with 5 keywords per page, that the downside is that your choices and options would be limited as well. Hardworking guys serious into their site SEO might want to try 20 keywords per page if they are keen.