how do I begin to write an essay in an exam?

First and Foremost; a Plan! Utilising the first 5-10 minutes of the exam to create a throrough plan of the direction of your essay is crucial as It prevents you losing direction midway through your essay and beginning to ramble. A plan that details your intent for the introduction, paragraph 1,2 3 (etc) and the concluision enables you to construct solid arguements that all flow into eachother well. Constructing a solid arguement requires correct engagement with the question; what is the question asking you? If it is a gothic literature question, for example, perhaps you are being asked to "assess the ways in which the writer creates a suspenseful/scary/sombre tone" then your first sentence should always be an inversion of the question - The writer successfully creates a suspenseful tone through his prolific use of pathetic fallacy throughout the novel. This illustrates to the examiner from the first sentence that you both understand the question and you are engaging with it. To prevent paragraphs of "waffle", I encourage students to follow a structure of PQA- POINT, (20) QUOTE (10), ANALYSIS. (70) throughout the essay. Each paragraph should be made up of these three components; The point you are trying to make e.g The author successfully creates a suspenceful tone through his prolific use of pathetic fallacy a quote that supports the point you are making- e.g "The dark night sky seemed animated and alive as the rain fell relentlessly, seemingly with unstoppable force, as though God had opened the heavens himself; A fork of lightning illuminated the dark and the ominious rumble of thunder filled their ears " analysing the quote you chose- picking out what lierary devices the author has used- has he used similes? dynamic adjectives? The affect of the semi colon? This is the section of your paragraph that requires the most "work". The act of dissecting your quote well is where many marks are to be made.  My methodology and experience follows that writing an essay for GCSE/A-level is a formulaic art. I obtained 100 percent in all my english literature examinations at A-level following this methodology which I also taught to 2 of my students who obtained high A grades at GCSE.