There really isn't any secret. On "Mini Falls" I used Photomatix Pro3 and just kept playing around until I got what I like. It was pretty straight forward. Except I went for more saturation than most would have. The only "secret" is that I didn't use Photomatix as it was meant to be used, i.e. three separate exposures. I used only one exposure RAW and saved it in three different .JPG exposures, on, over, and under by one stop. If I had to duplicate it again I probably couldn't do it.
Now, Into the Unknown, is a different story. First, converted to HDR as above. Second, converted to B&W and heavily manipulated in Photoshop until I got the effect you see. Truthfully, I have forgotten the process I used. I know it was several layers of editing. I guess I should have documented the process. Sorry. I have had several people ask me for the steps in Photoshop I used, and I'll be damned if I can remember. I'd be more than happy to share if I did. From now on, I'm going to save a duplicate file any Photoshop stuff in .PSD format. That way I can go back and trace the process.
Thank you for the compliment and interest.