One approach: Think of two terms or ideas that are similar but want distinguishing. "How is a foo different from a bar?" For instance, if you're looking to learn about data structures in Python, you might ask, "How is a dictionary different from a list?"
You can learn if your thought that they are similar is accurate, too: "How is a list different from a for loop?" might get some insightful discussion ... if you're lucky.
Of course, if you know sufficiently little about the subject matter, you might instead end up asking a question like
"How is a browser different from a hard drive?"
which, instead, discourages the expert from speaking with you (and makes them think that you're an idiot).
r/Fitness does a weekly "Moronic Monday", a judgment-free thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. I thought this seemed like a useful thing to have here - after all, the concepts discussed on LessWrong are probably at least a little harder to grasp than those of weightlifting. Plus, I have a few stupid questions of my own, so it doesn't seem unreasonable that other people might as well.