Ask Each Other the 36 Questions
In 1997, a group of social scientists shared a practical methodology outlining how they successfully created human closeness in a lab setting. In 2015, Mandy Len Catron published a personal experiment with the methodology in the New York Times titled, "To Fall in Love with Anyone, Do This." Then, my brain and everyone else's exploded when we realised all we had to do to fall in love was ask each other these 36 questions.
This is way too intense for a first date, but a couple dates in, throw this out as an idea and see if your love interest has heard of it. I'll warn you that I tried this with someone I'll call "work flirt," and things got too real too fast and we had to put the kibosh on the whole thing.