While the keyword meta tag has join the likes of the dinosaurs, ‘keywords’ are still valid for your site but just not in the form of a meta tag. They are important in the general text of your site. When you are structuring content for your home page, product page or design page consider using keywords your customers may enter into Google.  But, how do you know what keywords people are using in Google? Well, a simple tool provided by Google to identify useful keywords for their AdWords advertising product can also be used to help you identify different variations of keywords your customers might use to locate your product or service on the internet.

This tool shows you the number of times a keyword has been searched in Google for a particular region or globally for an average month. However, it also shows you alternate keyword ideas and  their popularity.

Head to https://adwords.google.com/select/KeywordToolExternal  and add a keyword of phrases in the form provided. Ensure you select the “Advanced Options and Filters” and choose the regions you want to limit you results for.

Try “t shirt” as an example. You will the number of times that keyword has been searched plus other suggestions such as “t-shirts”, “create t shirt” and “funny t shirts”.

Take note of the other three columns in this result:

Competition: refers to the number of Google AdWords using that keyword in their Google ad and varies from high to low. It does not relate to the number of websites using that keyword however you can make a fair assumption if they keyword is used in their ad it would also be used on their site.

Global Monthly Searches: refers to the average number of Google users that search that query globally for each month over a 12 month period.

Local Monthly Searches: refers to the average number of Google users that search that query within the local region you specified each month over a 12 month period.

Consider using some of these other variants of keywords within your site content. “T shirt” is a good example. The first time you use it use “t shirt” (the most common way its used by Google users) then other times you use this word use different versions such as “t-shirt”, “tee shirt” and “tshirt”.

BUT a word of warning : Avoid keyword stuffing, which according to Google “refers to the practice of loading a webpage with keywords in an attempt to manipulate a site’s ranking in Google’s search results.”

Source: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=66358

Google has recently tweaked its search algorithm to detect websites that blatantly stuff their site with keywords.