One of the biggest mistaken many CIMA studnets are doing is not completing mock exams under exam conditions. Operational Case Study exams are stressful. You need to attempt few, under exam conditions just to get used to tits format. It will help you better manage the limited time you have during the exam, so you can be as efficient and productive as possible.

This is very important step that just cannot be skipped. After you've read the requirement few times, decide how many points you want to make. Write the heading, leave some space below. Prepare the structure of your answer first and only then start developing your points. When you spend time on planning your solution, I can promise you that the writing is going to become much easier. That is the skill you can only learn by practising, that is why it is so important to complete as many mocks as possible. 

When you read the requirement, your brain start to figuring out the points. Our thought process is not very structured, we can talk about one things, then switch to the end and then come back to add 2 more points that should be included in the middle. Using a word processor helps a lot here. Preparing the correct structure of the answer helps tidy up the ideas we have in our head, helps to structure them, so the examiner will be able to understand what is that you are trying to say.