Generally the girls prefer to take love than to give. But guys should be careful and make sure that she is completely comfortable with the way you love her.
Firstly, girls like the guys who treat them special in public. When everyone are watching, especially in the places where the girls crowd is also heavy, or at least among her friends, make sure you show much more love on your girl. That makes her friends feel jealous about her and if the girl is clever enough, she might even understand that jealous feeling of her friends.
At that point of time, you mean a lot to your girl, and the reflection of your love will be immediately shown after girl's friends leave.