I think her style has evolved a lot. I mean 4-5 years ago she wore Ralph Lauren almost exclusively. These days she's been branching out in terms of designers favoring Dior, Valentino, Chanel, Emanuel Ungaro, Phi, Carolina Herrera, Marchesa, Peter Som, Phillip Lim, and Carmen Marc Valvo. She's also branched out in terms of the colors and textures. She used to favor pastels and satin. She'll still wear that sometimes but she also wears a lot of brighter, bolder colors, and prints.
I do think that she has a basic idea of what works on her though. She experiments with different kinds of looks but I think she has a basic understanding that she looks best in simple, classic styles