For example if I know I need to explain Blockchain to someone I would sit down before-hand and write a simple explanation, rehearse it until I memorize it, then I would explain it to the person, the first time I explain it I might be slow and rusty, but if I have to explain it to another person I will be a bit better, etc. etc. so by the time someone else asks me to explain it, I sound like a genius :)
This can apply to Technical, Scientific, Personal, and any kind of content/concepts really. You can use this practice to improve your social skills too and tell interesting stories!