I studied la deuxieme guerre mondiale, so the three main events were; l'appel de Charles de Gaulle, la signature de l'armistice and la rafle de vel d'hiv. In my introduction, you need to introduce your topic and if you can drop in some buzz phrases like 'on ne aurait nier que' the examiners will love it and it will get you off to a good start. You need to learn some good paragraph starters, emotive adjectives and linking phrases as well as making sure that you have a good understanding of the tenses (parfat, imparfait, présent, futur et subjonctif). I can help with this and send some example essays which I have produced myself where you can steal some phrases!