Being a mirror
It has been proven that if you mirror someone else’s body language, there is a higher chance that a person will like you. It does not always have to be in a romantic setting either, it can be a business meeting or anything else. Amazing what just a few movements of the body can do.
Make sure though that you are not just doing exactly what they are, right after they do it. They will definitely be noticing this and think it’s weird or even creepy. Slowly change your body position over time to mirror there’s, but do not put a lot of emphasis on it.