*feels inadequate*
Guys! I studied crazily hard for all of my subjects!
Although, I guess if I did have a 'bludge subject', it was literature, I only did one practice exam-like essay before the exam (but that's because my teacher told me to! If she hadn't said that, I would have done a practice exam a day). And also, I had written so many essays throughout the year and was doing uni level literature, both of which helped immensely. In any case, I was confident that I could afford to bludge.
I remember playing a game throughout last year I liked to call 'if I stopped studying now...' and would guess what my ENTER would be if I stopped studying then and only did the bare minimum in class (as in, I'd learn it all but not revise). My estimate was about 95 by August, but I considered that it's easier, for example, to make the difference between 80 and 85 than what it is to make the difference between 95 and 96. The difficulty (or, looking at this thread, the level of intrinsic smartness) required to get higher scores goes up exponentially, which is why I continued to madly study past August.
I can give you a rather extreme story: My friend got 99.95 (in WA) after deciding that he had 'given up' and stopped studying by the term 3 holidays. He is insanely smart though (he got an average of 95% across all his subjects last semester and I can say for sure that he procrastinated a lot).