Starting off with her head, Yuffie has short hair (to match her tomboy personality), held up with a silver metal headband with green bandana/hairband
thing attached, showing in the back of it. Yuffie wears no earrings, most likely because it's a bother for her active lifestyle, and she's not much of a girly girl anyway.
Down to her shirt. Yuffie wears a green turtleneck sweater, cut-off so so it exposes her stomach.
It also has a shoulder guard, which is attached to the protector on her left arm. This can be used as a shield. The shoulder guard is held to
her top with belts. Square loves to put belts on their characters.
Yuffie's right handed, she uses the arm to handle and throw her weapon. She wears a leather glove to hold her sharp weapons,
with a flesh colored fishnet covering her lower arm - most likely. Her left arm has that shield, which connects to her top with a symbol-like
ornament, and has green ribbons coming down from it.
Moving on to her shorts, Yuffie wears khaki shorts which are quite baggy. The top button is undone, exposing her belly
button. Upon closer inspection, it appears the shorts aren't even zipped up. ^^;; There are also metal belts on her thigh attaching her
stockings to her undies.
On to her legs. On her left leg, Yuffie wears another metal cuff and flesh-colored fishnets similar to on her right arm. It
was suggested that this could be for holding materia. Yuffie's right leg is bare. She wears high midcalf loose socks, a bit like the popular
loose white socks that Japanese schoolgirls wear. Yuffie has kick-butt yellow sneakers. Rock on.
Other Variations
In other games where Yuffie plays a role, she where the same ninja outfit with distinct changes depending on the mood of the game.
Ehrgeiz: Red outfit, instead of green. I think the abundance of red suits her agressive personality best.
Kingdom Hearts: Less armor and more colors (like a blue top and a yellow scarf), fitting for the young-oriented game.
Advent Children: Darker, military-like version of original outfit. Everyone in AC get a darker makeover.