Here's an old school technique that really works if you use it at the right time.
Mirroring is the idea of copying someone else's body language in order to make them feel more similar to you and thus increase rapport.
Now obviously this is a more subtle tactic and it doesn't create magical reactions.
But, recently I was re-introduced to the idea through a book studying the science behind charisma and I've been having some great results on dates by simply mirroring the girl's body language first, then leading the body language into a more relaxed and open place.
I start by mirroring her sitting posture for 3-5 minutes until we're on the same wavelength. Then I slowly start to open up my body language more and start presenting more interested body language (leaning in etc).
So far if I do this the right way the girl almost always responds and starts copying my body language at which point I can start to escalate much easier.
So it's something to try out once you have some rapport with a girl.