Establish a budget for your trip to Australia and New Zealand. If you're not planning on working while backpacking, your current savings will be your only source of money while traveling. While it's not necessary to plan every single stop and hostel stay along the way, having an idea of how long you'll be able to travel on your savings is essential to a successful backpacking trip. Factor in costs such as plane tickets, bus tickets, hostels, food, supplies and entertainment.
Plan your route through Australia and New Zealand. Think about your goals for backpacking in Australia and New Zealand. Are you going to see the cities, spend time on the beaches, trek through the outback or hike in the mountains? Or, are you going to do all of these? Plan your route around what you want to see and experience, keeping in mind that you'll have to start your travels in a major city that you can fly into.
Prepare your supplies and plan how to pack your backpack. Depending on your goals for backpacking (hiking, working, seeing the sights), you'll need a particular set of supplies. Remember that you'll be carrying all of your supplies with you as you move from place to place, and keep your pack as light as possible while still having the essentials. Regardless of your goals, you'll need to at least travel with clothing and footwear, toiletries, basic first aid supplies and medications.
Contact potential employers if you plan to work while backpacking. Australia participates in a Working Holiday Visa program that allows foreigners to find work and earn income while in Australia. You can work for up to 12 months on the Working Holiday Visa, if you're between the ages of 18 and 30. If you don't have a particular skill you would be able to parlay into a job abroad, consider horticultural work through the World Wide Opportunities on Organic Farms program.
Secure your visa and any other documentation you need to travel. Make sure that your passport is up to date and you have an Australian visa of the type appropriate to your trip (tourist or working). Allow yourself at least one month to secure an Australian visa, more if you're applying for a work visa.