As regards to her perfect skin, in that ponyryder interview she says that she uses a perfect world moisturiser and checks and balances face wash by origins.
I don't know what it is about this stuff but ever since i've started using it (I use the perfect world face wash instead though) my skin has just become so even toned and clean looking, and is no longer dull but glowing. Maybe it's just the moisturiser that does this, but really this stuff is great.
Also i'm sure her healthy lifestyle helps too