The purpose of an essay's introduction is to introduce the topic and main ideas. You want to give the reader a feel for what your essay is going to be about. The introduction can be several sentences long or just one sentence, depending on the essay and the purpose. For example, an introduction in an essay about leadership could include, a leader is someone who inspires others around him to be better.
An essential part of an essay's introduction is the thesis statement. A thesis statement is one sentence that concisely sums up your essay's theme or purpose. In some cases, the thesis statement can be the introduction by itself if the sentence is concise and eliminates the need for more explanation. In the example of an essay about leadership, the thesis statement could be as the famous saying goes, "Leaders are made, not born."
The body of an essay is its main section. The length of an essay's body depends on a number of factors, but a good general rule for a normal essay is to have a three-paragraph body. The body is where you will present your main arguments and back them up with facts and details. Each paragraph should support and develop a main idea, and each paragraph should begin with a concise sentence that introduces the point. In the essay about leadership, the paragraphs could cover the key attributes of a leader, such as patience, passion and hard work.
An essay's conclusion is used to wrap up your main ideas and drive home your point. Like the introduction, the conclusion is one paragraph and can be several sentences or just one if it is powerful enough. The conclusion is your last chance to make your point to the reader, so taking the time to make it memorable is important. Part of a conclusion to our essay about leadership could be, a great leader doesn't necessarily have to be the most intelligent person in the group, but she should be a diligent worker, patient and willing to listen to everyone she is leading.