If you are only targeting very popular keywords, you may be missing out on a huge amount of traffic. It is not easy to rank in the top 10 for competitive search terms, but it can be remarkably simple to rank well for related niche keywords. Do not overlook the vast amount of users who are searching for those terms.
Assume that there are 100 people searching for a few niche terms that are related to your topic, every day. If you rank well for those niche keywords, that is 3000 new users who may be coming to your site each month. If you are only targeting the competitive search terms, and are having a difficult time ranking well for those terms, by all means, add new pages that target the relevant niche terms. You might be pleasantly surprised by the amount of new traffic you receive.
The first step to identifying the niche keywords you should be targeting is by scanning your log files. How are people finding your site now? What phrases are they searching for?
Next, ask friends and family what they would search for if they wanted to find your site. Try to avoid directing their thought processes. In other words, no helpful hints. Just let them come up with a list of two or three phrases they would use on their own.
Finally, do what the pros do. Use the tools available on the net to determine what niche phrases are not only popular, but are also relatively easy to rank well for. The best tool on the net today for this is Wordtracker. Use the free trial version, or get all the help you need with an affordable subscription plan. How does it work? You enter some keywords, and Wordtracker tells you how often people search for them, as well as how many competing sites use those keywords. This is also a great way to discover popular misspellings of words!
In summary, niche search terms can bring in tons of extra traffic. When designing your SEO plan, don't forget to include niche keywords.