Find cheapest flights on net, then get flightcenter to match the price.
I am flying back to the UK with the family in March on Singapore airlines and got the flights $1500 cheaper that what was offered by any high street travel agent. I think I found the cheapest flights on http://www.travel.com.au/
If you're going to hire a car, try to avoid the major companies - they really do charge a premium.
Depending on the time of year and deals on, friends of mine have booked and paid for flights from Hong Kong or Singapore in local currency to Europe and just got flights in Australian $ to get to those hubs.
Also be careful of using multiple different carriers to save money, Air Asia X etc, make sure you leave a decent time between each flight, if you miss a connecting flight you gonna be in trouble, where if you use a single carrier they are normally good a fixing up an alternative flight.
For hotels I generally use http://www.hotelclub.com/
for major cities.