How can I learn what my key mistakes are in Speaking?
The only way to learn what mistakes are causing you to fail is to get feedback from an IELTS expert.
A good English teacher can help you correct your mistakes with grammar and vocabulary, but only an IELTS expert understands exactly what an examiner expects at a Band 7 or 8. We are very good at telling students what mistakes are going to cause them to fail their Speaking test and how they can work on overcoming their mistakes so that they can pass their IETLS test.
Here is how to book a mock speaking test.