1. Know the syllabus itself - especially, helps you know what points to talk about in a business report/essay for a certain topic's INFLUENCES/PROCESSES/STRATEGIES.
2. Know the syllabus content - the dot-points themselves will not suffice (especially for short answers and the extended responses), you need to know the actual content (e.g. definitions, explanations, etc.) under each dot-point.
3. Know your case study or case studies - the key element to doing fantastic in the essay section (IV).
4. Know how to write a properly structured business report and/or business essay - look at exemplar reports/essays from past students and practise writing your own if needed.
5. Past Papers - the updated Business Studies syllabus papers are the 2012 and 2013 HSC papers.
You might want to get access to CSSA 2012 and 2013 + Independent 2012 and 2013.
And perhaps, other school trials.