Aaron Wall provided some of his "secrets" to keyword research on the WordTracker blog. It's about ensuring you have developed the best possible seed list - because the final list is only as good as the seed list you start with. This goes pretty deep, so it is a good read for ideas on your next keyword research project.
http://learn.wordtracker.com/articles/keyword-inspiration-aaron-wall-of-seobookcom-shares-his-secrets-1/
