How do I structure the perfect History exam essay?

Structure is imperative, and must be taken into account whenever you're writing an exam response. If a response includes all the relevant content, examples, and explanation, without a clear and fluid structure, all quality will be lost. You must therefore follow a formula that will make every answer, regardless of quality, clear-cut, easy to read, and on course for top marks.
1) Introduction - every response must have a clear introduction. This is a paragraph used to outline context to the question, your own ideas, and your argumentative standpoint. Once you have introduced the topic, and your views relating to it, you then have the opportunity to "sign-post" your essay - showing the reader what you are going to be talking about, and when. Introductions are arguably the most important component of an essay. From the outset, a marker can gauge your understanding of content, and whether your argument has legs. Once signposted, you clearly state your argument in response to the question, and set out to prove it in the main body.
2) Main Body - the essay is made up of paragraphs, each outlining an individual point. The number of paragraphs depends on the question and the depth of your argument. You may have 2 extremely detailed points, and will therefore delve into them more so than a few outlining views. Either way, each paragraph should be structured as follows: a topic sentence which outlines the paragraph's answer to the question, and a following sentence to clarify its relevance. You will then delve further into this point, providing examples and relevant explanations, which all link back to the question. Paragraphs end with a closing statement, which very briefly states the relevance of the paragraph, and its link to the question at hand.
3) Conclusion - finally, one must always write a conclusion to summarise their overall views. A conclusion essentially takes everything into account and answers the question at hand. It must begin with an opening sentence, stating your response to the question, followed by a quick summary of all your points - never provide new information, only overview what has already been discussed. Like the main body, finish it with a punchy closing statement which answers the question and states your position. By following such a formula, you may expect top marks from a response with quality content and argument.