For those who don't know, the UMAT is a challenging pre-medical test every prospective doctor needs to sit in Australia and New Zealand. In most universities, it is a major consideration for gaining an interview and a seat in medicine. Unlike other requirements, such as good performance in final-year-school or university exams, it's not necessarily based so much on knowledge as it is on non verbal and verbal problem solving skills and empathy. This is the official site which outlines the exam and basic preparation for them: http://umat.acer.edu.au/prepare/preparation-strategy .
I'd always be reading a good novel before I slept - it was a habit, I needed to before I slept. On top of that, I read things like TIME magazine, science/technical journals. it's even easier to do it nowadays, and it's not a chore at all - a lot of the things you can read are really interesting. The I Fucking LoveScience Facebook/ Web page is a good place to start - it has a great science blog where it talks about recent advancements, which are all interesting and fun to read. All of this makes comprehension/ reading speed go up, and also gives random pieces of knowledge to you, which who knows, may just get you more marks. That's exactly what you want in this kind of test!