Hmm, well, personality wise, they would have to be casual, apathetic, irrational, assertive, and quirky, cause that way they would directly contrast with what I consider to be my personality.
As far as attractiveness goes, she'd be right on the line between cute and sexy, so she could be cute when she wanted and sexy when
I wanted she wanted. She'd like the color teal, always wear jeans, and be really slender, and she'd be physically fit enough to beat me up. She'd be a freeloading hacker who would sometimes take her laptop and disappear for weeks at a time, only to come back hungry and full of internet memes. She'd also be good at math. She'd be into really indie music, and would hate any mainstream band/artist, although she'd secretly like a few but she'd never admit that to me. She'd always be willing to try new things, and would ditch me if I was being stubborn. But in the end, she'd always come back.
In the end, I'd teach her how to think, and she'd teach me how to live.
Wow. I did not know I was that much of a hopeless romantic.
