Thanks for the kind words. 99.9% of H&M's denim looks like pure shit. This just happens to be the one pair they have made that look cool and arent extremely skinny fitting. I was pretty surprised when I first saw them since they have great details like metal suspender buttons and a cinch back. They look far more like something RRL would produce than H&M.
It is pretty much just on camera flash against a white wall. For these ones I have been dodging out the wall so its pure white then bringing it back down to a bit of a grey so it looks even. You really dont have to go that high tech if you dont want though. The main thing is you have to set everything manually or the flash will try to expose for the wall and under expose everything.
Here is a photo that I just had published today using almost the same setup.