Hello! That sounds like an exciting trip to the amazing cities of Australia. Here are some travel tips for you.

Best Time to Visit:
The best time to visit these Australian cities is in the spring (September - November) when the weather is pleasant. Although winters (June - August) too can be a good time for a visit as it's a bit cooler, which might be more comfortable.

Route and Accessibility:
The most convenient way to travel to Australia is by air. You can land at Sydney airport, which is well connected globally. Once in the country, domestic flights, long-distance trains, buses, and self-drive are great options to move between cities.

Accommodation and Booking:
Australia has a wide range of accommodations, from high-end hotels to budget hostels. It's best to book your accommodations in advance, through reputed websites. Melbourne and Sydney are big cities, so consider staying central or close to public transport to save commute time.

Clothing and Essentials:
Pack weather-appropriate clothing. If you're visiting in spring, lightweight clothing and a light jacket for cooler evenings would be apt. Don't forget your swimwear for those fantastic Australian beaches. Carry sunscreen, sunglasses, and a hat to protect against UV rays which can be strong in Australia.

Health and Safety:
Australia is generally a safe destination. However, always keep an eye on your belongings, especially in popular tourist spots or crowded places. If you go swimming or snorkeling, please follow local warnings and guidance related to marine creatures.

Local Etiquette and Respect:
Australians are laid-back and friendly. A firm handshake is a common greeting. Tipping is not obligatory, but it's common to round up or tip 10% for good service in restaurants. Australians Have great respect for the environment, so follow all guidelines regarding litter, wildlife, and natural spaces.