Use analogies to explain technical concepts

A good way to explain a technical idea is to use an analogy. Though they have limitations, analogies are helpful in explaining an unfamiliar idea in terms of a familiar one. One of the best analogies I ever heard compared a firewall to a bank teller. When you enter a bank, you don’t just go into the vault and get your money. Instead, you go to a window, where the teller verifies your identity and determines that you have enough money. The teller goes to the vault, brings it back to the window, gives it to you, and then you leave.