Face
First thing that any boy notices is her face. By face it does not mean with the color, it actually means with the gesture. Boys always love girls with smiling-face. No boy likes girls with angry faces.
Girls with glasses
Girls with glasses are always considered as cute and studious by boys. Boys will often think that these kinds of girls will not like their friends. Boys also often hesitate to make friendship with such girls, but they like them so much.
Dress
Dressing sense matters the most. Your dressing should be classy enough to fascinate a man and make him fall for you. Go for what is there in trend. Boy notice that how much the girl is confident with her dress. If I am not wrong there is this saying that Indian boy wants his girlfriend to wear western dress and wife to wear Indian dress.
Eyes
Usually, when you first meet new people you look straight in their eyes. Your eyes can tell a lot about your personality, your mood and about what you think of the other person. When a guy looks at you for the first time, he looks straight into your eyes and reads the subconscious message that you are sending him. Eyes never lie. To know the nature of girls, boys often look up to their eyes.