i got a 39 as well and my results were A+,A,A+...my friend thinks our cohort brought us down a bit-i wouldn't have a clue.
so here are some other suggestions,that i don't think people have talked about...!
my advice is to recognise that what you are learning is interesting and to try and have some fun.
also for each sac/ assessment for the area of study-go over that specific area in all the past exams since 2006. take your time and go through every question-even if it takes you more than half an hour to complete a 5 mark question. you might think its taking a while but it really is worth it because you'll gain experience in how to answer that question and ones alike-and as you go through the questions in past exams it will take you less time and you will be more comfortable and confident in answering them.
also in the weeks leading up to the exam,go through all the practice exams again but try to complete them in the set amount of time allocated.
what really helped me was making cue cards. my friend did health&hd this year and for each of her sacs she made cue cards with definitions,case studies and possible questions that might be asked for the area they were studying at the time and she practiced them. she did this for each area of study and at the end of the year,she was able to practice them for her exam(i also presume she did the past practice exams and that she went over these cue cards throughout the year) anyway,she ended up getting a perfect score of 50 for h&hd.
i only started making cue cards in term 3 holidays but it really did help a lot-make sure you say them out loud,so its easier to remember what you've written and also say them aloud to anyone that will listen-even get your friends to test you and you can return the favour with them(i did this a few times although,i probably should done it more).
thats all i can think of at the moment but as a recap;
1. go through specific,relevant questions in past exams for each sac
2. make cue cards and practice them as you go,throughout the entire year!
3. go through the practice exams in the weeks leading up to the actual exam
4. try to make it fun!!
hmmm also maybe check out youtube for videos,such as on conflicts within the basin...i think you can find a few on population-i didnt do this too much but its just for fun:)