I was in third year last year, didn't get to do the jc but I did get a distinction in my business mock. To be honest just focus on key words and what they mean. With the way the new exam is done you won't often be asked straight out to define terms, you'll have to read between the lines a bit and make sure you insert your knowledge into your answers. It can seem like the questions are very abstract, but just remember that you're always trying to show the examiner what you know about the subject. My teacher always said to structure our answers like this: key word, explanation, example. This way you're showing actual knowledge from the course, which will earn you marks. Also, try to keep your answer within the context of the question if that makes sense. Basically, the exam is mostly based on your ability to apply business studies to real-life situations.
Other than this, there is some stuff you will be able to learn completely off and use directly in the exam, such as the accounts, meanings of acronyms etc.
Hopefully that all made sense, and if you have any more questions just let me know!