Firstly I would plan your essay by splitting your argument into agree and disagree (for the disagree section you need to identify another country that may have been responsible for the division of Germany, or even another external factor such as the Cold War tensions themselves). You need to introduce your position on the question, sign-posting where your essay will go and what you will be exploring. Be very clear with your argument and make sure you introduce it as soon as possible. This will help you to remain focused in your essay. The begin the main body of your essay with your argument and later analyse the counter-argument against your own to show the ways in which your argument is better. For example, you could argue that by creating Bizonia in January 1947, the Americans were responsible for creating a divisive climate in Germany and did not seek unification. Here some historical evidence would be required about the events that led up to the creation of Bizonia and can also include events thereafter (such as the subsequent creation of Trizonia) to substantiate your argument. This can be your first of several points and I advise following the PEEL (point, evidence, explanation, link) framework if ypu struggle to structure your argument. This is also ensures that each point is well substantiated and also that you remain focused on the question at all times. The same can be send for counter-argument points (which you can have integrated into your argument points if you feel comfortable enough to do so smoothly) however here you must be clear of whilst this is an argument, why yours is more valid. For example, Stalin also acted in a way that disregarded the unification of Germany and instead pursued land reform and nationalisation policies to, arguably, antagonise the USA. However, Stalin's policies can be seen as part of a broader attempt to strengthen Germany into a position where they could re-unify whereas America had deliberately strengthened the divide between the two states by joining with Britain (and later France) to reinforce the Cold War divide of West and East. Here I have given another argument but explained how my argument is stronger and undermined the other side of the argument whilst keeping the question in mind and not going off on a tangent. After doing this in the main body of the essay, you need to conclude with your judgement and the points you have analysed to reach this judgement whilst keeping the question as your focus at all times.