I didn't really make any massive changes, kept doing what I was doing but became a lot more aware of what I was eating, mainly due to horrific morning sickness that didn't really go away all pregnancy! Not sure if it's the same in Aus but the first thing I did was find an LMC, in my case a midwife. The best piece of advice she gave me was not to get too worked up/concerned about doing the right thing, trust your instincts and go with what feels right. In terms of eating, a good rule of thumb is if you have gotten food poisoning from it be careful about eating it. I was wary of chicken for a long time, and avoided things like preprepared salads and anything that might have been sitting there a while. I personally ate sushi but only when I knew it was fresh and hadn't been sitting out, but again trust your instincts, I think your body is pretty good at telling you what you need to eat!
Sleep as much as you can get away with, cos trust me it will be a thing of the past as soon as bubs arrives! Pregnancy yoga can be a really great time to connect with the new life growing inside you, plus it's really great exercise (certainly helped me feel less like an alien hippo!).
Biggest thing though, just enjoy it! You really aren't pregnant for that long in the grand scheme of things (although towards the end it feels like forever) and you're doing the most amazing things a human can do.