The foundation of a good search engine optimization campagin is selecting the best keywords that your potential viewers will use to find your website. If you select keywords which won't bring targeted traffic to your site or if you select keywords which no one searches for, all the time and effort that you spend on optimizing your web site for the search engines will be wasted. For your target audience to find your site on the search engines, your page must contain keywords that match those that your targeted audience is typing into the search queries. Here I'm going to recommend 2 very useful free websites that will help refine your keyword list. These 2 websites are http://inventory.overture.com/d/searchinventory/suggestion/ and https://adwords.google.com/select/KeywordToolExternal. Enter one of your keywords into the search box and it will generate a list of popular search terms related to your keywords. Look through the list and refine your keywords accordingly.