We first note Salinger's vividness of description. The reader could care less about the street names or other various paraphernalia, but is given them any way. These more or less serve to promote the reality of Holden's thought while showing his attentiveness to detail.
Salinger's attentiveness to detail is supplemented by an attentiveness to the rhythms of speech. Whenever a character is placing the syllable on a different beat, or even emphasizing a certain syllable, the dialogue reflects the accent via italics. Additionally, the rhythms of speech are mirrored by the rhythms of thought: the paragraphs are broken not merely by subject matter but also by emphasis of thought. Shorter paragraphs get implicitly more emphasis in the reader's mind, and Salinger uses this fact to his credit.
The events of this book are not organized haphazardly, and in many instances Salinger displays his brilliance in the juxtaposition of two events in order to display contradictions and foils. For example, at one point he places Holden's account of children right next to his account of actors in order to display the honesty of one versus the falseness of the other. At another, he juxtaposes the inconsideration of Ackley with Holden's own inconsideration, thus displaying the hypocrisy of Holden's criticisms.
Holden's jargon is consistent and very enlightening. For example, Holden's use of qualifiers such as "if you want to know the truth," "I know what I'm talking about," or "I'm not kidding" serve to emphasize how unsure Holden is of what he's saying or how well he'll be received. Holden also has a tendency to use the undefined second-person pronoun, "you." This ungrammatical usage emphasizes the disillusionment Holden feels because almost no one sees the world like he does-he constantly has to reassure himself that others would do the same thing or feel the same way. Finally, Holden senses sometimes that the words he is using are not quite right, that language fails him: "I don't exactly know what I mean by that," he says at one point, "but I mean it." This admission of the difficulties of writing only adds to the realism of the novel.
Holden's criticism of society is brutally honest: his profanity is atrocious, and he levels his knife against everything from religion to homosexuality without flinching. This is, after all, an adolescent's mind. Similarly, we also note the psychological exactness with which Salinger details Holden's thoughts, which reflect the symptoms of depression as well as the common biases which plague human nature.
Finally, Salinger knows when to break the heaviness of his subject matter with humor. For example, take Holden's conversation with the cabbie Horwitz about how fish stay alive in the winter. It's a classic. Sometimes there is a fine line between seriousness and humor, and Salinger dances deftly between the two.