Tools of Characterization
Characterization in Life Is Beautiful (La vita è bella)
Actions
Just like in real life, actions help us discern who's who in Life Is Beautiful. Consider Guido. There's a kinetic, clownish energy in everything he does, but even though he acts the goof, he's also able to solve Dr. Lessing's riddles in record time. He's also willing to take risks to accomplish his goals and doesn't give up.
These actions show us that Guido's an intelligent guy, even if he acts the fool. Check out the scene where he undermines the idea of racial superiority while seemingly giving a lecture on the very subject.
He's also a determined man, whether that's to win Dora's heart or protect his son from the realities of the camp. In this way, Guido's part of a long line of Shakespearian fools who use their wits to outsmart people in authority.
Dora's much the same. Although constrained by her social standing, we see Dora's free spirit hidden underneath what society expects of her. She laughs at Guido's jokes, is all in for late-night ice cream, and is willing to crawl under a table in her party dress to steal a smooch.
The ultimate act that shows her free spirt is, of course, riding off with Guido on a green horse to live (mostly) happily ever after.
Occupation
Occupation is a great tool of characterization, too. In Life Is Beautiful, the characters who work jobs lower on the social ladder are more sympathetic. Meanwhile, the characters who work jobs within the government or other social institutions are just the worst. And the Nazi guards—fuggedaboutit.
Uncle Eliseo is a great example. He operates a hotel restaurant, which isn't a bad gig but also isn't tops, socially speaking. Yet, the man's intellectual, philosophical, and kind. He doesn't view himself as a servant but as a man who can better himself and those around him through serving. He even helps a Nazi guard who trips in front of him—a woman who's leading him into the gas chamber.
Ferruccio's another good example. An upholsterer and a good friend, he helps Guido win Dora's affection despite getting his car wrecked in the process. We could see ourselves hanging out with him. Talk about Schopenhauer, maybe even write some bad poetry about loving life…or just hang out.
On the other hand, we have characters like Rodolfo and the principal. In a telling scene, they both discuss a math problem that asks how much money the state would save if it eliminated 300,000 undesirable citizens. Both discuss it as if the question asked how many apples you need to make applesauce.
Note that Rodolfo is a government official and the principal is, well, a principal (of a school for kids). Both have a hand in shaping society and could help make it a better place. Yet unlike Eliseo and Ferruccio, they don't.
Clothing
Clothing is another tool of characterization, and this one draws from history. Consider the uniforms worn by the prisoners at the concentration camp; they're all the same. Men wear vertically-striped shirt and pants, while the women wear drab dresses and head scarves.
The clothes have no hint of individuality except for the ID number tattooed onto the prisoners. The clothing seems designed to strip the prisoners of any individuality, dehumanizing them in the eyes of their captors.
On the other hand, the soldiers wear uniforms. There are certainly similarities between the uniforms because, you know, that's how armies work. But the overall purpose of the uniform is to express pride in the individual, their country, and their accomplishments. Medals, for example, are signposts for these very individual qualities.
Life Is Beautiful takes these characterizations and flips them on their head. The soldiers have few distinctions in their personalities. Overall, they're stern, ill-tempered, and cruel. And with the exception of Dr. Lessing, none of them are provided with even a name. Their characterization is to be cogs in the heartless machinery of systemized death that was Nazi Germany.
By contrast, the Jews and other Holocaust victims have unique personalities. Guido is funny, Eliseo is wise, and Bartolomeo is helpful with a fair bit of street smarts. The German soldiers attempt to strip them of these personalities—literally taking their personal clothes and piling them up. Yet through their interactions, we see their humanity loud and clear.