The best thing for reducing stress in the HSC is consistency (as others have pointed out). PLEASE be consistent!! Keep on top of all your work! Don't avoid homework, don't start set tasks late, try to be revising through the whole year! Don't get distracted when your studying - cut out the distractions. Its much better to study 3 hours with complete and utter concentration on the task at hand than to study 8 hours while daydreaming/getting distracted/etc. Not only that, but it leaves you alot more time to still enjoy life if your efficient!
Importantly, if you stuff up an assessment/exam, DON'T GIVE UP. I remember, I had this completely unrealistic view that every assessment task would be perfect. I remember stuffing the mid-course exams, and being SHATTERED at the end of it all. Overall, however, they didn't count for all that much. Thats not to say it's okay to stuff up, but if things just go bad in one thing, don't worry too much.
Anyway, I think the most important thing about this year is to try your best. It's worth it really, if you do well you'll never regret trying hard in the hsc. All your time at school till now in the eyes of the world means nothing. You could've duxed years 7-11, but it accounts for nothing after this. And if you try hard and still don't do great, you'd probably have done a lot worse if you didn't try, and at least you'll have a solid hsc to show employers/pursue uni. I really think 5 hours is excessive BTW. I would be really exhausted. Maybe really close to exams you could step it up a notch.
Anyway, good luck! I know its tiring but don't give up!
