You look like you have a nice face so that;s working for you.
A girl that smiles, makes eye contact, and is friendly will generally attract teenage boys, as well as guys in general. Unless he's a total manchild, it's not like teenage boys are seekers and destroyers of the vagina. Many teenage boys do get intimidated by the idea of actual sex, so acting like a whore won't always give you positive results. It will for a few boys, but I'm guessing you want to attract a certain boy.
Being nice, friendly, and open will get you in the door in almost any circumstance.
Well the girl has to be attractive, but it's more then that. They have been attractive girls that I thought were pretty but I did not "like then" certain girls just have a difference to them that I can't put down.
Attraction is almost entirely about looks. However luckily for you guys tend to be much less picky than girls. At your age though a larger number of guys than you realize are still very shy, maybe you should be a bit more proactive in showing that you are interested when you meet someone.