Well, the thing is that I've already completed year 12 and now I need to change my top preferences as I've found out that they are not going to easily guarantee me a job when I graduate...yes I know that it's a little late that I'm doing this now, but I seriously need to find a course that I'm interested in but simultaneously will guarantee me a job when I graduate..it's all so hard 
Whoops got you confused with OP!
Well, work experience and grades get you the interview for the job, how you present yourself in the interview ultimately determines whether you get the job. So, imo find what interests you and follow it. Get decent grades and try getting as much exposure in the industry as possible. These days it's difficult to get a job after graduating, especially with all the qualifications one can have, their experience, the number of positions available, the number of applications etc. I've read/heard stories about how some job vacancies can have hundreds of applications but there may only be 5 jobs available. They then eliminate by grades and work experience for interviews.
Write down all the courses that you're interested in, research them - look at job stability, salary, potential etc then you decide. Then change your preferences to what you want after results are released. Also, if you're sold on a course or ideal career and you don't think your ATAR will get you an offer for it then make sure you adjust your preferences accordingly so that #2,3... are alternative ways of getting to it, whether it be via transfer after 1st year, doing a honours/masters degree or whatever. I highly recommend that you don't put something completely different as your #2, unless you really are undecided about your future. If that's the case then stick with general degrees like science, commerce, arts etc. Then you can transfer or do post grad studies or whatever. The weekend is enough time to research this stuff!
