One of the most important things to practise for IELTS speaking part 2 is choosing your topic quickly. Take this question for example:
Describe a situation in which you were very polite. You should explain
- where the situation took place
- how you showed that you were polite
- and why you needed to be so polite.
It would be easy to waste your one-minute preparation time worrying about what situation to choose. If you still haven't decided what to talk about when the examiner asks you to start speaking, you'll be in real trouble!
Give yourself just 10 seconds to choose your polite situation. It doesn't really matter what situation you choose; the key is to give yourself enough time to prepare some ideas.