Good keywords are frequently searched for (high demand) but not being targeted by many other websites (low competition). There are a number of tools out there that can help you find them.

Wordtracker

The best tool out there, Wordtracker is one of the most essential SEO tools. To use Wordtracker:

- Go to the Wordtracker website (http://www.wordtracker.com)and pay $7 for 24 hours