There was not complete agreement among New Critics of the 20th century. Ransom supported New Criticism but did not like the New Critic tendencies of ignoring culture and history. However, in general, New Criticism was a theory of criticism largely focused on close reading. The typical New Critic analyzed form, content, and interplay between the two. Also typically, the New Critic ignored historical context, autobiographical information about the author, authorial intention and reader response. By ignoring all of these, the New Critic focused on the individual work itself, looking closely at its themes, metaphors, structure, genre, and other formal qualities.
So, taking a New Critical approach, don't concern yourself with author's intent, your own response (as a reader), or historical background. Look at the metaphors, recurring symbols, character types, structure of the story, language, etc. For example, look at themes like rebellion and manipulation and how these are presented in the characters' personalities, thoughts, and actions.
Note, that while a New Critic approach really helps zero in on the text itself, such an approach can always be supplemented by other critical approaches such as reader-response, New Historicism, etc.
Each person who reads a book will look at it in a slightly different way. New Criticism takes this to another level, by suggesting that meaning making is a collaboration between the author and reader, in a sense. For example, you could argue that a teenager would react very differently to the events than a teacher or other adult.
You'll have to let us know the title of the novel you'd like to discuss.
New Criticism takes works as "ontological wholes" and examines various ways of making meaning from/in these works based on an interpretive model.
New Criticism, generally speaking, takes a contextual view of literature. Discussing a novel, for instance, by looking at both the cultural context of the author (and the likely meaning of the text given this context) and also at the interpretational or ideological context of the reader.
"Merging horizons" is part of the idea here. The reader brings certain associations and tendencies to a text and the text carries its own set of hermenuetical leanings. Reading, in this mode, is a navigation and a parsing out of the several ways of making meaning of the text - what the author probably meant, what the reader tends to think the work means, and what might fall in between.
Another way to put this is to say that New Criticism is interested in taking into account a reader's biases and looking at how that can create irony, multiple meanings, and ambiguity in the reading process. Meaning is made through the reading process, in this mode, not fixed within the letters of a text.
The chocolate war.