This is an answer which every guy will answer in a different way, so here’s what I find attractive about a girl:
Looks: Obviously the first thing people notice about each other. Here where it gets a little complex; I’m find traditionally good looking girls as well as ‘average’ looking girls equally attractive. The average looking girl drives me as crazy as a good looking one. However, unlike majority of the guys, I don’t sexually fantasize about either of the girls, until I’m sexually attracted to her. I’ve seen that sexual attraction only kicks in once there is a decent amount of physical contact(flirty touches, etc) or if the girl wears a mesmerizing perfume, or in rare cases, if the girl stands beside me, doing her work. In the third case, I start getting nervous and excited. It’s rare, because I’m used to hanging out with women. Diving further into it, whenever I’m attracted to a girl’s looks, thoughts run in my mind like, “She carries off that simple dress of her with ease. Even her simple hairstyle suits her. She also has a nice face.”
This goes on, until the girl flirts with me or we start exchanging glances, which start becoming frequent in which case, thoughts run in my mind; “I wonder how she would be as a girlfriend”, etc.
Voice: A girl I had a crush on, called me once, for a casual chat. Note, this was the first time I heard her voice. Her feminine voice drove me crazy, and I couldn’t smile like a retard.
Personality: Last, but not the least, the most important thing; personality. There were several hot girls who I was physically attracted to, but the moment they spoke and the way they treated others instantly turned me off. I personally am attracted to a girl who has a cheerful personality, with a mix of maturity. Someone who will watch TV shows with me, tag me in random memes, have deep talks with me, and support me during hard times, be it financial, physical, etc, and the most important; someone who treats ‘lower status’ people(as branded by society) as equally as the high status ones, and doesn’t mind the idea of having a coffee/tea at a small stall as a date, instead of the usual swanky Starbucks outlet.
Answering your question, personality is what I find the most attractive about a girl. Looks do matter, but they make up 25% of the equation.