In addition to this series of articles a while back on the photo.net web site about becoming a more creative photographer, he has recently been posting another series of articles called "Creativity in the Photoshop Darkroom" located at this link.
If you're interested in the options and techniques for how to tweak your photos to the next level in Photoshop, these articles are for you. Davis sometimes takes his photos further than I personally would, but regardless of that I think that most people can probably learn a great deal just from reading about his thought process and techniques. You can take away from these articles whatever works for you. Enjoy!