How do you guys text a girl..?

[Jonathan Idk]

I know I sound like a loser for asking this, and maybe I am, but HOW do you guys text girls?!
I've gotten girl's #'s before, but I never really knew how to text them. So they would text me for a little while, and afterwards they would just stop replying to messages, causing us to not text each other anymore.

Btw no girls talk to me at school, so I just get girl's #'s from social media, or Chatroullete. The people at my school sucks..

I used to text this one girl from my school who moved to another city, and I had NO trouble texting her. She even told me that I'm interesting to talk to. But all of a sudden she just STOPPED replying to my messages?! And now we don't even talk anymore. I doubt she was even THAT busy. My guessing is that she just thought I was boring.

Can you guys give me some examples on how you text girls? Thanks! I'm 18 btw.