I do 4 out of the 5 subjects you do (minus Chemistry, plus English Ext 1 and Society & Culture) and I know the same feeling of losing hope!
I sound bratty as, but in my first round of assessments I went incredibly well, coming first in all but one of my exams and I'm at a selective school. It was seriously surprising but I worked hard for it.
Next thing, half yearly's are in full motion and the pressure to succeed and maintain my reputation was too much to handle. I found that the stress blocked my mental state from moving forward and I broke down crying like a wimp a lot.
Here's what I did for each subject:
English Advanced
I consider this one of my best, but toughest subjects. The best advice I can give you is MAKE STUDY NOTES NOW. Even just opening up Word and creating a table with headings is the best jump start you can give yourself. Picking up quotes and examples from your texts along the way means you have a catalogue of choices when planning for your next assessment. Also, I've found the best way to structure your study notes is by brainstorming about three or so thesis statements that will be malleable for any question the BOS extract from the module statement (for the Discovery AOS obviously it's safer to have more theses because of the large mod. statement). Under each thesis, come up with three key points that support it, find examples from your core text (contextualise, meaning & effect, judgement... blah, blah, blah) then balance them with related texts and viola. It's a LOT of critical thinking and is vastly different from studying for 2 unit Maths, for example.
Biology
I love this subject because it's my only science course and it's so bloody straightforward. It's like here's the syllabus now go look it up on the internet. Obviously it has the reputation of being the easiest science (for the simple fact that it is) and therefore it's a process of creating study notes ->learning them -> past papers. Again, keeping up with study notes is key. If I don't get something straightaway there are a plethora of videos and resources to help you understand. In saying that, I know some do struggle with Biology (my best friend, for example) so it's best to ask your teacher, a friend that you know understands fully or do practise questions.
Advanced Maths
Do at least some mathematics every night. At my school, we take about 1-2 weeks to learn the topic with some exercises then we go through extra exercises to cement our knowledge and have a topic test. So I usually do the extra exercises as we go along and spend the extra time doing past papers (I'm constantly told there isn't enough time to do all the past papers before Trials and actual HSC exams).
Economics
Good god, I pray for us.
So much content. Summarise, summarise, summarise. Practise multiple choice, practise short answers, practise essays. Practise everything. Economics is extremely heavy in content (especially as I seriously have the world's most passionate and dedicated teacher) and it's important that you grasp difficult concepts as they come - spend time with your teacher when there are areas you don't understand. Keep up to date with current economics (I find the morning news or radio to and from school is sufficient but ABC has a lot of good, current content), memorise your graphs and statistics and use recent economic events as examples.
I'm only as experienced in the HSC as you are but hopefully some of what I have wrote is useful! I had a few disappointing results in my half yearly's and, as a result, I wallowed in my own sadness for too long these holidays haha. In the end, I'm almost thankful for less than satisfying results because they get you angry, then you accept it and move on (and usually upwards). Being at the top of the class is nice but I've found that having room for improvement is motivating when you have the right perspective. If you study to your full capacity and try your best, then no one can ask more of you.
As for forgetting things straightaway, it's important that you fully understand what you're absorbing. Cement this in your memory by: English = research on the internet, Biology = online videos, textbooks, diagrams, boredofstudies forums, Economics = I find my teacher is my greatest help (he repeats everything 10 times so its hard to forget), I also find investopedia has some basic videos that help you to get the gist of an idea, Maths = seriously, practise questions every night (minimum).
It'll be hard but we're already (kind of) half way there! At least you can console in the fact that I'm struggling with you haha. Also I'm trying to be motivated by the fact that uni next year will be much harder haha (not my best advice).
Good luck!
