In addition to what has been said by b^3, TT and MJRomeo in particular, I think most successful students have a goal.
A goal is important and can be anything: a uni course, an activity after VCE (schoolies, gap year, etc.), an occupation, freedom, a specific ATAR, and the list goes on. Having a goal is in itself a source of motivation. For me, I had occupation (on of doctor or actuary) and a numeric ATAR goal (99.15) that got me through VCE.
what happens if you set a goal and dont get it?
Its kinda disappointing.
If you are afraid of failing a goal, then your goals are probably too ambitious, goals shouldn't be feared of, they should be sources of motivation. I know some people say "'aim for the stars, if you fall, you will land amongst the clouds" (or something like that), but personally, I prefer to keep things realistic and plausible (because I don't want to be sad afterwards or lots of regrets).
I set my goal of 99.15 (to take that example of the two goals I had) in yr11 after playing around with atarcalc.com with study scores that I honestly though I can achieve accounting for my procrastination, hatred of physics, etc. For me, not only were those scores ones that I would be happy with, they were also scores I thought were realistic. They were neither too high or too low, I was honest with myself. They didn't reflect my potential (whatever that may be), they reflected my work ethic, and that's what matters.
If you (and make sure that it is YOU setting your goal and not your parents or anyone else - I never told my parents my goal of 99.15) aim realistically, and apply yourself accordingly (which shouldn't be hard if the goal is realistic), then you will pull though fine

edit: this is just how I tick, others prefer to aim huge and they don't mind falling short (even if it is short by a lot)
