Guys look for a girl who can hang with him and his friends. A girl who can hold her own when he isn't a around! They like a girl who isn't to high maintenance. She can be ready within ten minutes with little or no notice!
Most guys look and see if you are pretty or not, that's when they are in their teens, but most mature from that and I am not a guy so I can't tell you, ask one. If a guy likes you, he might act different around you or flirt (the obvious flirting) and stuff like that. I hope I helped. :)
guys who are jerks look for beauty. if hes worth it, he'll look for a nice personality and a gentle heart. if they like you, they might lightly tease you or seem closer than usual. they may also laugh a lot at your jokes :). you could just ask tho. :D