What are the key things to include in an introduction for an essay?

It is important to lay out your judgement with regard to the question whatever it may be, be concise and clear about where you stand. If there are any key terms or ideas that need explaining, it is a good idea to do this in the introduction so you do not have to keep repeating yourself throughout the essay. For example, if a question about President Nixon's foreign policy includes the term 'Realpolitik' you would explain that this refers to policies that are concerned more with practicality and a demonstration of power than doing what is morally sound. After having defined this key term you can use it throughout your essay without having to deliberate on what it means. You can introduce your argument by saying something along the lines of 'This essay will discuss...', it is important to avoid writing in the first person and instead you should write in the third person both in the introduction and throughout your essay.