I'm in a mixed high school... and can't communicate with women...

2 years before it I was in a boys only school. I now can't talk to any girls because I can never think of anything to say. I can talk to men easily because I've been with them before my temporary transfer to the boyschool, so I knew a little about them. But I never knew anything about the girls...

I can communicate with them online because you seem obliged to reply. That and I could think of something to say without looking weird. I try to follow them around, and contribute something if I knew something about the topic, but they usually have that "who the fuck are you?" look on their faces.

I was a girl's lab partner today... and we both acted like robots because we didn't show emotion. Everybody else was enjoying their experiments while she looked like "ugh, I wish I didn't come to school today."

I appear to be normal, my hair is just a bit long. I can't really smile or give a little one because of my braces. I'm not nerdy or anything...

So 4-ch, how can I start communicate with the other gender?