The ability to communicate ideas clearly and effectively is a vital tool in any exam. This is not to say that it is not equally important to have a detailed knowledge of the relevant period, but proper essay technique allows a candidate to demonstrate this knowledge to the examiner. Below I will set out a skeleton structure for an essay, together with some helpful tips.
Introduction
Often candidates find this the hardest part of the essay. The aim should be to breifly summarise what you believe the question is asking you to consider, and to give an outline of the points you will be writing about. You should avoid the temptation to include detail here that should go in the body of the text.
Side 1 of your essay
The best A Level essays advance arguments for and against the proposition in the question. For example if the question is: "Germany was primarily responsible for the outbreak of the First World War. Discuss" the best answers will consider points for and against this. Even if you intend to come down clearly for or against the question, it is still better to show the examiner that you are familiar with the arguments/points on both sides. Each new point should be in its own paragraph.
Side 2 of your essay
Having set out your arguments in support of (or against) the proposition in the question, you should then summarise the arguments on the other side.
Conclusion
Having set out the two sides, your final paragraph should be a conclusion. In this you should try and come to a view as to what your view on the question is. It is perfectly OK, and usually fair, to say that elements of both sides have some validity. It tends to be more important that you have good reasons to support your conclusions, rather than being assessed on whether they are "right". The purpose is to show you have considered and understood both sides, and made a go at analysing them.
Some tips on writing essays
Having set out the structure of an essay above, I have also included some general writing tips below:
1) Take the time to do a plan.
This can be hard in exams, where time always feels like a pressure. However it is worth taking 5 minutes to sketch out the points you would like to make, and the order you would like to make them in. A well organised argument makes it easier for the examiner to give you marks.
2) Don't try and make too many points.
You are better off making 4 points well than 7 in a rush. Choose the best ones and have confidence in them.
3) Paragraph structure
When writing each paragraph, try and follow this pattern. In the first sentance explain what the paragraph will be about. In the next few sentances explain your points and cite any evidence you can to support your points. In the final sentance, summarise the points made above into one concise and memorable sentance.
4) Introduction and conclusion
Leave yourself enough time to do these well, as examiners will pay a great deal of attention to them. However, avoid the temptation to make them too long. Rather than repeat what is in the body of the text, use these as a chance to make effective summaries and to look at the question in a broader way.