Yeahhh i did far less work than i should have in year 11. I still put effort into assessments and exams and all, but still that effort didn't kick in until the night before. I was doing well at the start of the year, but that all turned to shit really, i just kept telling myself it didn't count and i'd start for year 12, which i have, but i'm regretting not doing more work through the year, at least to trial study techniques and get into the habit of working every night, but i'm also finding in a few of my subjects, chemistry in particular, there were certain basic things that i needed for this year that i never learnt properly, so i'm having to review prelim stuff as well.
So yeah, to all the little year 10ers out there that are planning to just completely bludge through year 11 and kick in for the HSC, don't. Don't burn yourself out. And don't stress too much about assessments and all, just use them as a measurment of how you're going. But at least pay attention in all of your classes and get into the habit of doing some study regularly, it's easier to build up than just expect to start all at once.