Before using keywords for your site, it is always better to check for the popularity of these sub theme keywords. Some or all of the tools mentioned in the keywords tools section could be utilized to measure the popularity of these keywords.

Based on the popularity count of these tools we should come up with a descending order listing of our most unused but good key phrase. These are our good target keywords. As the competition increases on the keywords, deeper optimization then just building keyword specific pages will have to be done.

Variations on sub- theme words:

This is the word- play to get into the mind of the user.

Now our set of 25 to 30 keywords will be expanded to include singular-plural word combinations, juxtaposing the same words in a different combination, using synonyms, building on the list of words using Thesaurus & a good dictionary.

The ideal set of keywords/ key phrases is to come up with around 70-100 possible ways of looking for that web site on the search engines (our keyphrases)

Research on these variations of the sub theme keywords for actually combing up with the combinations that are relatively un optimized for yet popular. At the end of this exercise we will have the ranked list of keywords, which we can start optimizing for.

General observations & other nuggets:

When using google to check for the competing pages through the SERP house the keyphrase in quotes. This will do the exact phrase searching for the phrase that we are optimizing for. Now to have a real feel of the actual competition on this phrase use the adword tool.

Typically offline competition for the business & online competition are not equivalent. The client needs to be driven out of this mindset. Online the competition for us depends on the key-phrases that we choose rather then the industry or the competition chosen keywords.

Another useful tip is to watch out for the ranking of the subpages on the SERPS page.

A higher occurenec of a sub- page suggests a lesser competitive key- phrase.

Keep excel sheets handy to work out on your key words

Here is a benchmark: If the site is fairly well optimized, and has a focused theme, then the combined total number of visitors from secondary variations of the main keyword phrase, should be higher than the number of visitors from your main phrase by itself.

Another yardstick can be that 20% of your search traffic reach you through your primary theme words. Another 20% through the sub theme words & their combos & the remaining 60% is fractional. A true pyramid.

Keep the keyword density on your pages in between 5-20% while optimizing. The latest talking optimization based on keywords is that almost none of the things mentioned above might apply as it is. You create text based on the end user perspective & optimize for 5-6 keywords per page. Check your referrer stats & fine tune optimization.

Free Keyword Tools:

The first tool that can be used is Overture.

One trick is to check the keywords on all the Overture tools, US, UK, DE, FR and even JP. You would be surprised at the ideas you can come up with on the other O Tools that do not appear on the US one. Also, the de-pluralizing and match-drive-alphabetization some times does not appear on the other tools. Second tool of course is the word tracker.

Use Google adwords to check on the competition for the chosen phrases using the CPC barometer. Higher the CPC more the competition.

Another tool is at:

http://espotting.com/popups/keywordgenbox.asp

Yet another tool is Alta Vista PRISMA

One can use Refine search option of Teoma to arrive at more generic/Primary keywords. Another way of doing that could be through the DMOZ subcategory study.

Refining of key words can be done using the Server side data or the referrs log.

7Search.com's Keyword Suggestion Tool

http://conversion.7search.com/scripts/advertisertools/keywordsuggestion.aspx

http://conversion.7search.com/scripts/advertisertools/keywordsuggestion.aspx

More tools in here:

http://dmoz.org/Computers/Internet/Web_Design_and_Development/Authoring/Online_Tools/Keywords/

Once the keywords have been finalized lets look at the places where we can utilize them.