Why don't you show someone that you are interested in them by sending them a nice virtual gift?
This is a good way to break the ice and to start a conversation or even to compliment someone that you are already talking to.
Simply click on the gift icon. This will be one of the options under the persons
profile picture and they will receive a nice gift from you.
You can see who has been sending you gifts by checking the 'My profile page' under the heading 'My gifts'.