First of all, congratulations on your marks in English Standard and Studies of Religion II. I hope you are also happy with your performance in Business Studies.
Going forward, it is important to determine what exactly you need to study in preparation for your HSC exams, as this can assist in allocating the appropriate amount of time towards each of your subjects in an effective and efficient manner. Doing so (for both Mathematics Standard and Biology) involves determining a starting point. A good way to start preparing is by revisiting the syllabus document for both of these subjects. By taking a look at what each module/topic is and entails, you will improve your ability to manage your time as you draw from your own experience with each of those modules/topics, including specific concepts, i.e. which ones you found easy and which ones you found difficult. For example, if you found that the Critical Path Analysis subtopic of the Networks HSC topic was rather easy, you may allocate 2-3 days to revisit this topic, including consolidating your understanding of this topic which would involve completing relevant practice questions. Similarly, if, for instance, you found that The Normal Distribution subtopic of the Statistical Analysis HSC topic was rather difficult, you may wish to allocate more time to master this topic. In my opinion, one week would probably be enough. Of course, how much time you end up allocating is a decision you should make because only you are fully and truly aware of your capabilities.
Once you have applied this to all topics (which should result in you becoming much more comfortable and confident in your ability to effectively manipulate different mathematical concepts), your focus should shift to completing past HSC exam papers as this will allow you to ensure you are able to apply the knowledge you have gained and developed to actual exam questions. While you're doing so, you should also be monitoring your performance in those papers, including determining and addressing areas of improvement (if applicable). Being able to constantly do this across different papers, while simultaneously being able to complete multiple papers constitutes a substantial boost to your preparations, and will hopefully allow you to ensure optimal performance in your HSC exam.
I didn't take Biology, but generally, as with content-rich subjects, being organised is essential for effective preparation. This must be reflected in your notes in addition to material used to supplement your notes. This brings me to another important point, which is to not limit yourself to your own set of notes. Instead, ensure you obtain and make use of other sets of notes that might express particular concepts in a way that is clearer and easier to understand than how they are expressed within your own notes.
Here is a very good set of Biology notes covering all HSC content:
Hey! So recently I dropped out of school with everything that's going on so I'm going on a resource posting spree to help out y'all (more to come today and in the next couple of days) : p Uploading my Bio notes I created over Year 12 - was too...
boredofstudies.org
I hope this helps!