No, getting an approval letter doesn’t guarantee your visa. Australian High Commission may ask you some additional documents or information. Approval letter assures to some extend but doesn’t guarantee your visa.

1. Financial Requirements for the UK Visa Extension
2. Is it possible to go to the USA on Student Visa without TOEFL?
3. Visa for Switching to a MBA Program in Canada from UK
4. What should I answer if I'm asked about my future plans?
5. Will I get rejected for F1 visa if I've applied to only one university?
6. What should I answer if I’ve got admission to a university in same city as my brother’s?
7. How can I get a Social Security Number in USA?
8. What is a Tier 4 visa system for UK?
9. What is the age limit for study visa of Finland?
10. Will I get Australian visa for certificate-IV Networking?
11. How do I get a visa to Canada easily from Nigeria?
12. Admission and Visa process to study at your School
13. Can a school in Dubai issue a visa for my 15 yrs old sister to study in Dubai?
14. What is H1B visa for United States?
15. What are visa chances for Australian student visa?