Tools of Characterization
Characterization in Memento
Physical Appearances
We get used to Leonard pretty quickly. After all, we're basically following him around the whole movie. But Natalie's comment about his "freaky tattoos" reminds us that, yes: he has tattoos and they are pretty freaky. It makes sense for him to have tattoos to keep track of important things, but does he really need to get them all stylized and strewn about his body? While he praises the efficiency of his system, his tattoos don't look all that systematic. They look freaky.
We also have Teddy, whose sinister mustache and charming smile is basically all the characterization we need to understand him. And there's also Natalie, whose bruises, combined with her initial demeanor, give us the impression that she is a kind and mistreated person and should be pitied… until we start to realize the depth of her machinations.
Direct Characterization
Sometimes there's nothing better than blatant, in-your-face characterization: "Billy is mean" or "Teddy is a liar." This is especially true when you don't have any short-term memory, which is why Leonard writes notes that tell him (and us) what the different characters in his life are like… at least according to his perception of them. We learn that Natalie has lost someone, and that Teddy isn't to be trusted.