Hi Faust,
I'm not sure if this is what you're looking for, but usually i'm pretty good at this type of thing.
Each image is a little different.
Try desaturating the picture to begin with, but not completely. Then go into the channels pallette and duplicate a channel a couple times and make some simple masks, if you know how. What you're going for with the masks is to create ones with varying contrast, so you can get at the darks and lights to varying degrees. You'll need these as you go along. However, the effect can be achieved without masks.
Then think about the hue you want as the primary hue for the pic. This guy likes blues. They're moody. This hue, along with contrast, and the wispy nature of the photos themselves is what tricks the eyes and draws them in and provokes an emotional reaction to the photo. This is the secret.
When you have the hue right, work on the contrast, or vice versa, doesn't matter. His pics are very contrasty.
There's a couple things to help finish it that will make a big difference. You need to either make selections or use the masks as selections that I recommended you make at the beginning. These masks (or selections) would be used to either/or, further boost contrast in specific areas, but more importantly, add subtle changes to hues, and you'd do that by using the tools in
ps for colour, such as selective colour, colour balance, or curves, or whatever you're comfortable with. Even variations might work, as would duotones.
Also, consider experimenting with with screen and multiply modes and adding layer masks or just erase if you don't use layer masks. The multiply layers would be for the shadows of the pic, and the screen would be for the highlights. Reduce opacity for both of these layers though.
Also, add a layer on top of the layer order and put black gradients (to transparency) into the corners and darker regions that you want to de-emphasize and play with the layers' opacity. This will further draw the viewers focus into what you want them to be looking at, which in the case of your personal photo is the girl's face, esp her eyes and lips.
I've seen this thread several times here; it's a nice effect he does. With the original photo the effect can be duplicated just as he does it by measuring the hue/sat and other issues with the pic using photoshop's info pallette. This is a worthwhile tool to learn to use. I think most people aren't aware it exists or don't know how to use it.
I hope this helps. You'll have to experiment. A tutorial would be much easier to follow and since seeing this thread repeated several times I considered putting a tutorial together so people could get some ideas on how this is accomplished and return to it later, but last time I wrote one for this site several people trashed it so I'm done with tutorials here. Perhaps I'll put one up for this on my personal site if I get around to it.
I hope this helps anyway - if you like the effect but I was unclear, just pm me.
gl,
mig