The best way to divide an essay logically is to organize your information into paragraphs. An essay typically follows this format: Introductory Paragraph, Body Paragraph(s) (1-?), and Conclusion.
Your introductory paragraph should contain 3 things:
1. Give the reader a reason to read your essay: a good quote, analogy, or surprising fact that relates to the topic and that can grab the reader’s attention.
2. Summarize the main and important points of your topic that you are going to discuss in more detail. Briefly explain why it's important, a credible person that supports its importance, or where that information came from. The examples are simple and generic, but give you a place to start.
Ex: “According to scientist, Stephen Hawking...” or “The Oxford English Dictionary defines xyz as…”
3. State your thesis statement. Depending on the length and complexity of the essay (and your teacher's instructions), a thesis sentence could be one or more sentences. Usually, a short essay written in high school consists of one clear thesis sentence. This sentence should provide the reader with a clear idea of what the content of the paper will focus on, like a road map: explains the issue or topic and its important components, addresses relevant questions, states the position being taken and the claim/evidence that will support it, etc.
Ex: Because the monster in Mary Shelley's Frankenstein was a monstrous mishmash of the dead reborn, everyone drove him away out of fear and disgust, which turned Frankenstein into a desperate and vengeful being, doomed to wander the earth alone for all eternity.
There are usually more than one, typically three, or many, many more body paragraphs.
The purpose of the body paragraph is to begin breaking down the focus of your paper into organized chunks of information. Typically, you want to start by using a good transitional sentence that tells the reader what you are talking about--usually your first main point, as listed in the introduction, followed by supporting details, evidence, or examples from your research, and finally a closing sentence that tells the reader this 1st point is drawing to a close, and the second point is up next. Second and subsequent paragraphs follow the same formula, except with new ideas and supporting evidence. Ideally, if you have two examples for the first point in paragraph one, you want to give two examples for each point in subsequent paragraphs to give them equal weight.
The final paragraph should tie up all the loose ends and remind the reader (briefly) what they had read, (focus/topic, position/claim/end result/solution, etc. (What's applicable to your particular paper)) You don’t want to repeat in the conclusion word for word what you wrote in your introduction (or any other paragraph), but you do want to hit the important points. The point is to summarize (because they may have forgotten what the first point and support was by the time they got to number seven) and provide the reader with a sense of closure on the subject.