Before you get started you should brainstorm your ideas. The key to a good essay is a clear and detailed plan.
The structure of an essay:
The introduction should be kept short. It tells the reader what your essay is about.
The main body is the longest and important part of your essay. The main body consits of body paragraphs (see below).
The conclusion should be as short as the introduction and should summarize the main points made in your main body.
Each body paragraph should include:
1. A topic sentence that tells the reader what the paragraph is about.
2. A detailed explanation (how?, what?, why?) that adds deepth in order to convince the reader.
In terms of the examples you use, they should be specific, plausible and convincing.
Note: Your paragraphs are the key building blocks of your essay. One paragraph consists of a group of sentences on one particular theme. Thus every sentence is directly related to the main theme (topic sentence) and gives a paragraph its unity. A sentence which does not relate directly to the topic sentence belongs to a different paragraph.
There are two approaches how you can sturcture your main points.
The chronological approach is used when you write for instance an essay on American history.
The most common principle how you order your points in the thematic approach is the how significant you feel the theme to be in comparison to other themes. You can either progress from the most to the least important, or the other way round.
Source: Aczel, Richard. How to write an essay. Stuttgart: Ernst Klett Verlag, 2003.