SHORT VERSION:

Some (shy) girls sometimes give me looks at school like ("I might like you")

I chat them on FB about something casual, but even if I start a chat on FB twice with them, they still won't be the first ones to start, for a change.

If they like me, why can't they take the subtle hint and start talking to me?

--

I can recognize some (shy) girls at school that seem attracted to me by the way they sometimes look at me..

And I may then on FB start a chat about something casual like

"Hey, what did you answer to that homework?" or "Hey how did you exam go today?"

And we chat for some time and if no further conversation comes up
(from the stuff that I asked for in the first place)

Then, I might just throw in a joke or a funny remark about something relevant at school at the moment.

Now I don't want to seem obvious about getting to know classmate girls that I don't know too well yet but I find cute, but I can't be starter of a chat for more than 2 times, because then they might overthink that I am really attracted to them, but really I am just trying to start to get to become slightly closer with them.