I like to listen closely, find a couple of lesser pressed, but very needy buttons on the particular individual and press them just often enough. They don't have to be entirely free of being pressed, especially if the individual is in a mood, simply whatever will get them reeling the most at the given time is nice, but that's highly specialized to the individual ideally.
If I don't quite have a good idea of what the particular person responds to any given thing, I'd moreso start making little feeler statements, perhaps referring to someone with a little nickname at the end of a response, which can quickly convey how comfortable someone is with a given theme or kink. This is a very simplified version but if I think someone might like being called a baby, I can give it a shot, and generally they'll dismiss it if they can't stand it, and if they're already a blushy mess, well they certainly don't stand a chance.
You have to be attentive, and I'll perhaps dig a little bit through social media or prior interactions if I can, just to make sure I'm not being insulting by any means. I know I'm complicated enough, I enjoy abdl paraphernalia well enough, but I'm not a little, so referring to me as a baby just doesn't do it for me most of the time. I'm far more willing to indulge far more than I'm keen to be subjected to, which makes flustering others all the more easy.
