Search Engine Forums, SEO Forum

just research your keyword with google adwoeds, wordtrekker seobook.They are all free.

you can try Google adwords, seo book, spyfoo(paid), wordtracker etc. With these you can get your keyword and try to take those keywords that are less in demand and more searchable.

Choosing the right keywords for a website is an important part of the successful seo process. The successful SEO based on long-tail keywords. These keywords get less traffic than more generic terms, they are associated with more qualified traffic and visitors that are most likely further down their path.

Its depends on the contents of your sites. Use google keyword analysis tool for getting perfect keywords to work on your site.

Some of the Best Keyword Research Tool:

Google AdWords (Google Search-Based Keyword Tool)
Google Suggest (Google Instant for Popular Keyword Phrase)
Related Searches (Displayed below the results at bottom of the Search Result Page)
Google Wonder Wheel (Keyword Group)
Google Trends (Google insight Search)
Google Sets (Keyword Sets)

For Competitor's Keyword Analysis (Organic & PPC Keywords)
KeywordSpy[dot]com
SpyFu[dot]com

Try these Keyword Research Tool for selecting best keyword sets.

Remember those keywords may have high competition, but selecting and targeting them with proper SEO will give you good SEO Score.
Because you can easily achieve good ranking in less competitive keywords.
So use those keywords those are used by visitors

Google Adwords is best tool and most of the SEO analysts use the same.