First of all, Read the study text thoroughly and be comfortable with Law vocabulary used in the text. This will build your basic concept for the paper. I would not say that you read this text again and again, but once is good. Now, you will be able to understand the law.
The second step would be hard. You will need to remember case names and relate them with topics. This needs some time and little bit of hard work. But once you are done with this, Now you can easily write them in your own words. Remember that rote learning is not the key to pass the exam. However, to some extent it works like learning definitions and cases facts.
The last and final step is practicing exam kit. As more the questions you practice more will be the quality of your text. Remember that ACCA will not mark your paper against quantity, but they mark paper with quality of text. After following these steps I assure you that you will pass this exam with great margin.