I love the exchange between Shrek and Donkey where Shrek tries to explain ogres. It’s a great example of characterization, and also showing vs. telling.
Shrek could have told Donkey, “Ogres have layers,” but by using an analogy (onions), he illustrates (pun intended) it for Donkey. The exchange between them after Shrek’s declaration of “Ogres are like onions” further builds characterization for both of them.
Even though Donkey tries to sway Shrek to go with a more “pleasing” analogy (cake or parfait), Shrek sticks with his onion because it’s something he knows.
Like Shrek, our characters need to stick with what they know. Drawing an analogy with something unfamiliar to our characters damages their credibility and betrays our readers’ trust.
While we’re on the topic of onions/layers, we need to be sure to peel back the layers of our characters and get to the core of who they are. If we don’t know the core, the layers won’t matter.
Forms, interviews, personality quizzes, etc. are all good ways to get to know our characters. I use several different methods, but my favorite is the Psychological Type Profiles. I can access links to quizzes, etc. from this site.
Your own character building techniques will help you find the core and build layers around it . . . kind of like an onion growing. Starting small and expanding until full potential is reached.
In my current WIP, the MC would be likely to use analogies involving wood/whittling because it’s what she knows.
How well do you know your characters? What kinds of analogies would they use?