I’ve written a few posts in the past on the value of creating your own keyword list, data mining for keywords, new and different sources for keywords, etc. They are like WAMPUM, and worth real money if you know where to look and how to use them.
Aaron Wall has what I consider an invaluable post–resource/tutorial, really– on Creating a Sweet High Value Keyword List. I defer to him on this– expansive info as usual from a long-haul SEO.
I started a keyword resource for myself a year or so ago on the advice of a guy I was working with at the time. It was the best thing that ever came out of his mouth. I was new to conversion copy/sales copy and I wanted a resource list that I could turn to for instant “action” words when my brain went cold and numb. Since then I’ve expanded it, ripping keywords and phrases from ad copy, web copy, and sales copy everywhere I turn. But I’ve also found it really helpful to make niche keyword lists when I begin writing job copy for clients. And Aaron’s post will refuel that task in the future.