Start from what the person you are explaining to already genuinely knows, and build outward from there using an analogy or comparison to something familiar, rather than jumping straight into technical terms or jargon that assumes knowledge they do not actually have yet, since a good analogy does more of the real explanatory work than a technically precise but unfamiliar definition ever will for a genuine beginner.
Explain why the idea actually matters before diving into the technical detail itself, since context about its relevance and importance helps people follow and retain the specifics that come afterward considerably better than detail presented without any framing around it first. Break the idea down into small, clearly sequential steps rather than presenting the whole thing at once as a single dense block, since a complex idea almost always becomes more digestible once it is broken into a logical, one-thing-at-a-time sequence rather than delivered all together.
Check for genuine understanding as you go along, rather than only checking in at the very end, since a quick does that make sense so far catches confusion early, while it is still small and easy to clarify, rather than letting it compound silently across the entire explanation. It is genuinely worth knowing that truly simplifying a complex idea, rather than just using simpler-sounding words for the same underlying complexity, actually requires you yourself to understand the idea quite deeply, so if you find yourself struggling to explain something simply, that struggle is often a useful signal that you should understand the topic more thoroughly yourself first.
Example: A student explaining a complex economics concept to a friend outside the field started with a familiar everyday analogy, checked in periodically with does that make sense so far, and broke the explanation into clear sequential steps, which helped their friend genuinely grasp an idea that a textbook definition alone had failed to convey.
One practical tip: Start with a familiar analogy and check for genuine understanding as you go, rather than only at the end, since a quick does that make sense so far catches confusion early, while it is still small and easy to clear up.