IMHO, all of the following contributed to this look: background, lighting, liquify, excess noise reduction, large-R USM (or equivalent) + some good old fashioned dodging and burning.
Of course, a list like the one above is almost completely useless because a huge number of possibilities and design choices open up at each step along the path, so it's almost impossible for someone to come up with a similar look unless they were very experienced and made the correct choices at each step.
If you want to learn how to do something like this, IMHO, a much better approach would be to supply an appropriate starting image of your own and then have the folks on this forum demonstrate what they can come up with. Then, get the PS file (and other settings) of the "winning" effort and then study it in incredible detail.
Just my $0.02,
Tom M