1. Thoroughly analyze past papers
2. Work on choosing a dimension of essay writing that sits well with you. For example: if you feel that you can write more fluidly and coherently on current affairs based essays, you can choose to study those topics in more detail.
3. Write down all the different ways the examiner has put forth the statement of different essays. For example: if you are preparing for a possible essay on education, you can see from past papers what the examiner has asked regarding education over the years. In 2018, the essay on education was focused solely on Higher Education. In 2019, the essay topic was "Classrooms decide the future of a nation". You can see that one essay is more focused and the other is broader in terms of what you can address in your writing.
4. The 3rd point will also help you understand the nature of the essay you are attempting. From the example above, it is clear that the 2018 essay only asked for your input regarding higher education. You can trace its problems from a lower level but your main objective is to develop arguments centered around higher education. The 2019 essay topic is very broad in comparison to 2018. You can write on all aspects of education, primary, secondary, and tertiary. The point is that you need to be able to identify what has been asked of you and remain strictly to the point. Context is necessary but the bulk of your essay should focus on THE issue.
5. The next step is making outlines. Make outlines of as many past essays as possible. Try to squeeze your time frame for making outlines. For example: if you start making outlines and it takes you about an hour to make a comprehensive outline, try to practice as much as you can to get this done within 30-35 minutes. You can do it by, again, covering all aspects of the topic. When you have practiced extensive outline making you will find it easier on exam day to (a)write quickly, (b)cover all aspects and leave time to ponder on any newer aspects that might have been asked by the examiner, and (c)save time for writing a thorough introduction.
6. The introduction is pivotal to your essay. Try to write intros of as many essays as possible and have them checked by qualified mentors. Again, practicing intros extensively will also help you cut down your time because it will increase your writing and thinking speed.
7. Do search for relevant quotes and statistics because they boost your essay and gives it a professional touch.
8. Work on recommendations as much as possible. If you leave an essay, specifically one based on current affairs, without recommendations in your exam you will drastically lower your chances of even passing the exam. Work on writing as many short term, long term, and medium term solutions to different issues as possible. Try to be creative and think originally.

I hope all this helps you with your preparation.