Initially it'll be her looks that interests a guy to spend time with the girl to see if she's worth spending time on.
Some of what I think are universal traits he'll be looking for in a woman once he's comfortable with her:
1. She's able to take care of herself
2. Emotionally stable
4. Enjoys life
7. Not a flake
Although, just like girls with guys, different guys are attracted to different women initially. Some guys might love piercings and tattoos on their women. Some might only date business women. It might even be as ridiculous as going for women who only wear red high heels.
If you're asking this information in hopes of self-improvement rather than just an opinion then here it is. I believe that if a woman truly believes herself beautiful, then she'll convince men around her that she is beautiful as well. If you see yourself as a prize, men will too.
i think that what lawhsia said was true. my significant other even TOLD me "i only started talking to you because I thought you were cute. but now I love you for who you are" now. that's not to say that people who aren't the stereotypical "cute" won't get anybody. I'M certainly not. but HE thinks I am.
and like he said, different guys like different girls. however. I believe they are all NOT attracted to a similar thing. girls who try to be somebody else. if you can just MAGICALLY turn into what you think they want, then I don't think they'll REALLY like you. so I always get a little annoyed when I see girls and guys asking what the opposite sex looks for in a guy. yeah there are certain KNOWN things. like good hygiene and stuff like that. someone who's not a jerk. but as far as the unique characteristics, you need to just find someone who likes who you already are. like, even stuff you may not like about yourself. my "friend" says he loves that I'm interesting. well. other people call it strange. or weird. or freaky. but. I found someone who looks at that as a GOOD thing. :)