General advice I would give:
1) Be very very organised - have a schedule and stick to it
2) Work harder than you think you need to
3) If the syllabus hasn't changed since I have done it, consider subscribing to Business Review magazine - it has helped me in my exams
4) Where possible, consider getting an A Level exam practice book that show you model answers for different grades
5) Do as many past exam papers as you can, with as much practice as you can - get as much feedback from your online tutor as possible
6) The hardest thing for me when I was studying business studies wasn't the knowledge - that was relatively easy to understand. The hard part is producing the sort of answers you need in the exam. Also, there's a lot to remember for 6 papers.
7) Produce critical and analytical answers. I've included a lot of rhetorical questions as part of my criticism in my answers, which is kind of frown upon at uni. However, it helped me score the high grades I needed.
8) Remember formulas, as they won't be provided in the exam. Most of them will be from accounting. If you don't bring a calculator with you to the exam, it's your fault.
9) You will end up with long notes, so keep a ringbinder or 2 handy for them
10) There's a recommended business textbook to read up on. I don't know how much the syllabus has changed, but if it hasn't I can refer the book to you.
11) Another hard thing is to produce good answers in under timed conditions - no point in producing a 5 page essay if it doesn't help you in the exam. Aim to do 1000 word answers in the appropriate allocated time.
12) Draw graphs or diagrams as appropriate in the exam. It really helps.
13) When doing the exams, get the simple and easy marks out of the way as quickly as you can. They tend not to give you a lot of marks for these questions. After that, allocate the remaining time you have for the other questions.
14) Use whatever case studies they give you and apply as much knowledge you have learned to the case study as you can. Quote/reference facts from the case study in your answers.
15) Look through the specification with a fine tooth-comb. If it's not part of the spec, don't need to learn it. Business studies has a lot of stuff to learn as it is.
16) Memorise and copy out defintions. Use references if appropriate. It will save you time during the exam, and you will be able to articulate exactly what you mean in as few words as possible.
17) Spend no more than 5 minutes planning out essay answers; ideally spend 2 minutes or less. Plans will be given marks as well
18) Learn to get into 'flow' state before the exam. If needs be, do practice questions under timed conditions before the exam. It helps warm you up.
19) It's nice to finish the answer in an exam, but if you're running over time, it's better to move on. There's diminishing returns to completing an exam answer, and you usually score more from moving on than sticking at it.
Let me know if you have any specific questions.