Purely from observation. I do not intend to offend anyone, as I have friends/know people that may fall into some categories.
Los Angeles (and surrounding areas): Anything goes
Scenesters: "takes a lot of money to look cheap" - very eclectic, vintage, ghetto-fab, w/ "key" pieces (designer bag, chanel earrings or necklace, over-the-knee boots, flashy hoodies, fly sneakers, lots of gold, Louboutin's, etc)
Bros (and bro-hoes): I.E. Travis Barker - black bandana on head, spiky hair, form fitting black shirt, flashy belt buckle, may be wearing an armband, baggy jeans, clean sneakers, asian inspired sleeves, etc
Girls - big (fake) boobs, blond hair (even if you aren't caucasion) w/ dark streaks, Frankie B's or any other really low jeans, lots of layers (w/ the bra showing), lots of eyemakeup w/ pale lips, etc.
Label whores: no explanation needed. Just blatant usage of brands.
Rachel Zoe clones: If it's in a magazine, they are rockin it. Over accessorized.
Rockabilly: Dark hair (or really blond or red), red lips, black eyeliner, perfect hair, retro fashion, cuffed jeans, plaid shirts, mul. tattoos or peircings, pompadours, sideburns, etc.
There are so many styles out there. I love fashion and individuality!