Honestly; there is no simple answer to that question. There are so many different types if people out there that you cant say that every gut looks for a particular thing in a girl. My advice don't worry about what guys look for in girls. Look for someone that is compatible in your likes and interests.
one thing is that she pays attention to him. Guys mature two years under girls so that's like he has the maturity of a 12 year old. I am 26 i have been with the same guy for 7 years and I have asked him a lot of questions about this kind of stuff. Guys don't necessary care about girls at that age as much as we care about them. So that's why you have to stand out. You have to let him know you, don't lie about anything, like your older then you are or you are better then what you really are. Guys aren't into holding hands or showing their girl off, so don;t get discouraged. But to answer that question guys like sweet girls, and at that age, all looks girlfriend. Guys like the way girls hair just flows on their shoulders, the smell of their perfume, and make sure your not pushy, you may send him away. I hope I was helpful, good luck