Mainly girls that aren't extremely "girly", can actually think for themselves, and altogether are nice people.
As for looks... I'm not picky, but if I have to choose, than boobs that aren't the size of Pluto (not flat-chested, per say, I just don't like giganto-boobs), a slender build. I'm not saying "I don't like fat people" I'm just saying I like to look at a slightly smaller build.
As for turn-offs... tattoos, piercings, huge boobs (as stated earlier), and American Southern accents. I don't know why, but a Southern accent is not sweet and innocent to me. It's grating and piercing, like a rat letting out a call before it scurries into the darkness. Maybe it's the fact that half of my family is from the South and about ninety percent of them are assholes, so I think "family member, don't want incest and/or an asshole" and run away. Eastern accents, on the other hand...