Spending time in an English-speaking country is a really essential experience for the English-learners as well as the best way to study the language. However, I believe that there are many other strategies for learning English, which are useful enough. 

In the first place, studying in an English-speaking country such as Australia gives you a variety of opportunities to improve your speaking and listening skills. Moreover, you practice your English while doing ordinary things, for instance, shopping. Consequently, you become more self-confident. Being overseas is the best way to learn the language effectively. 

Secondly, providing that the learner is hard-working enough, they can learn English even in their own country. The English Language Schools provide their students with a wide range of opportunities to master the language. Furthermore, there are different methods to practice your skills such as watching English television, reading English books, magazines, etc. The combination of some of these methods might be a really useful strategy.