The mood in his shots comes largely from the light; he knows it well and uses it effectively. Much of his work appears to be done early in the morning or late in the day when the light is quite interesting.
He employs a lot of tools; dodging and burning, heavy vignettes, selective focus (that at times seems to be enhances through a Gaussian blur) and in many of his shots, he goes for very low contrast (a technique that I personally don't feel is pariticlarly effective and his shots would be stronger if he added contrast). He gently desaturates parts of his image to make them look like they are taken in a dry and dusty environment. He definitely does photocompositing in some of these pieces
This one is another obvious photocomposite:
In your shots, look at using some of the selection tools that are available in Photoshop; I use a lot of them in my work, but the Quick Selection tool is the one I use most often; halos are something I watch for too and generally I use minimal feathering of my sections if I notice halos. There are ways to remove them in places if you happen to do so by accident, but the process is time-consuming (I clone out the halo with a very small brush that is somewhat soft).