As an exercise:
Think of a roughly trivial topic you know a good deal about now, but didn’t always. I’m going to use my recent experience of learning more about baking with sourdough as an example.
Now imagine or remember a time in the past before you had this more thorough knowledge when you were in a room with maybe four or five other people. Imagine that the other people in the room then all have the knowledge that you have now and you’re the only one who lacks it. Now imagine that you are talking about the topic a little bit. Saying enough to reveal how little you know about it as well as the fact that you don’t realize there may be more to know.
The other people don’t say much about it. The conversation moves on, it’s not a major event. But think about what the other people may have thought about what you were saying.
For me, this puts me in a mind to consider all the unknown-unknowns I may be unknowingly tripping over at all times. Sometimes when I’m around people who I suspect have knowledge that I don’t on a given topic I’ll very explicitly say something like, “please let me know if I’m doing something very stupid here - I want to know and I won’t be offended at all” (walking around the garden with more experienced gardeners comes to mind).
An older note called this retroactive ignorance acknowledgment