Start by asking the wrong ones. For me, it took a while to notice when I had even a stupid question to ask (possibly some combination of mild social anxiety and generally wanting to come across as smart & well-informed had stifled this impulse), so this might take a little bit of practice.

Sometimes your interlocutor will answer your suboptimal questions, and that will give you time to think of what you really want to know, and possibly a few extra hints for figuring it out. But at least as often your interlocutor will take your interest as a cue that they can just go ahead and tell you nonrelated things about the subject at hand.