The University of Queensland provides this interesting summary for students preparing to study there:

When you arrive in Australia, or at the University of Queensland, one of your first problems may be with the English language. Even if you have studied English for many years in your home country, some of what you hear may at first escape you. You may also have difficulty in expressing yourself in English. This is a common experience for people who have not lived in an English speaking country previously. Try not to be discouraged. Here are some ideas to help you with the difficulties you may experience:

People speak too fast - Spoken English will sound very rapid to you at first. Don't worry - your ability to understand will improve just as rapidly. People won't mind if you ask them to repeat what they have said or to speak at a slower pace.
Vocabulary - Many common words in Australia and many words used in university life may not be in your vocabulary. Don't be surprised. Just remember that textbook English is not the same as the language used in everyday life.
The Australian Macquarie Dictionary will be more helpful than the Oxford or Webster's dictionary in understanding Australian English.
The Australian accent - Remember that every English speaking country has its own particular accent and way of pronouncing English words. You will find the Australian pronunciation of many familiar words quite different from what you are used to. Don't worry about this; you will soon get used to the sound of the Australian accent.
Slang - Australians, particularly students, use a lot of slang. Remember that student slang is just as hard for older Australians to understand as it is for you! Slang can be very specialised and it is always changing. If you don't understand a word or phrase, ask the speaker what it means and how it should be used.
Abbreviations - Australians like to abbreviate or shorten words, even down to initial letters. So food technology is usually shortened to "food tech", "breakfast" becomes "brekkie", and a tutorial becomes a "tute", "International Admissions Section" becomes "IAS", "Farm Animal Medicine and Production" becomes "FAMP". If you don't know, ask!
Anxiety - You may feel nervous the first time you interact with English speaking people who don't understand your native accent or language, that is quite natural. However, you will feel more and more at ease as the semester progresses and soon discover that you communicate quite effectively with the Australian speaker. You can ask the International Student Advisers about ways to meet other students.

Written language
You will come across many new words as you continue your studies. You may also find that the grammar used in some textbooks makes them difficult to understand. Here are some suggestions that may be of assistance:

Use a good dictionary - translate as many technical and academic words as you can into your own language. This will slow your reading, but it will vastly improve your understanding and increase your vocabulary range. Revise your list of new words and expressions as often as you can.
Remember every academic subject has it's own "language" and it may use words and expressions in ways which are quite different from ordinary day-to-day use of the English language. You will find that the same applies to the textbooks you are using.
It is sometimes possible to "guess" the meaning of a word from its context. Try to develop your guessing ability.
Learn to recognise the key words used to develop logical arguments within sentences and paragraphs.
Take notes of the way a book is organised into sections, chapters etc. The headings may assist you to quickly get a general idea of the contents.
The Learning Assistance Advisers, at Student Support Services, will assist you acquiring the skills you need constructing and writing an essay, thesis or report and with different techniques you can use when working your way through lots of required reading. (eg "skimming").
Body language
Every culture has certain 'typical' behaviours; ways of standing, moving, using hands, eyes, arms, nodding the head, etc. Usually there are meanings associated with these movements or gestures, and the meaning may be different in Australia from the meaning attached in your own culture.

In Australia, for example, it is usual to look someone in the eye when you are talking to him or her. Australians think that this shows directness, attention and sincerity; but in another culture, it may be considered as impolite or improper to do this. In some cultures, it is an insult if someone gives you something with the left hand - in Australia it makes no difference.

You will soon notice these differences when you start interacting with Australians. Similar observations are of course important anywhere else in the world. It is important that we learn to recognise, appreciate and respect difference as long as it is not offensive. If you are not sure ask people you know or staff at the University.