The explanation ladder is a simple but powerful technique: ask for the same concept explained at increasing levels of sophistication, from a five-year-old's version up through an expert's version. Each rung builds on the intuition from the one before it.
This works because most people's actual gap isn't intelligence β it's never having the concept broken down at the right starting point. The 5-year-old version gives you the core intuition without jargon; the 25-year-old version adds real mechanics; the expert version adds the nuance and edge cases that actually separate competence from fluency.
A good habit is climbing the whole ladder even for things you think you already understand β many people discover their "understanding" was actually just familiarity with the vocabulary, not the underlying mechanism.