Looks: Yuffie is very cute. She has very dark brown (maybe black?) hair and what looks to me like brown or moss green eyes. Short, thin, and proportionate.
Style: Yuffie probably has the most complicated and detailed outfit of the whole FF7 cast. She wears a short turtle-neck dark green tank and yellow/beige colored shorts with the fly down. Aside from that are several pieces of armor and other paraphernalia.
Personality: Energetic, happy, loud, over-confident. Yuffie acts selfish, obnoxious, and immature. But those are only surface traits.
Beneath the bubbly exterior is a young girl who cares deeply about those around her, even if she doesn't always show it in the most blatant ways. She's always working to prove herself to others, prove how strong, fast, or clever she is. In some ways she is similar to Asuka from Evangelion. But Yuffie has a certain maturity to her that only peeks out occasionally. She has to be pretty smart to leave Wutai and strike out on her own to restore her village, relying on her own capabilities. Oh yeah, this chick is tough.
Skills: Various ninja skills and she can throw really good. She uses all kinds of cool ninja-style weapons (that I will not go into here) and she’s also a good thief. DON'T TURN YOUR BACK ON HER FOR A SECOND. Seriously, don't try to name her. She WILL rob you blind. But that's what makes her so special. :D