In parts 2 and 3 of the IELTS speaking test, you need to make quick decisions about what to talk about. Always try to talk about a topic you have prepared or something you know about. Here are some examples:
Part 2: Describe a law in your country.
Advice: Choose a typical IELTS topic like "guns". Explain why people in your country can/can't own a gun, and talk about the pros and cons of this law. There is a chapter on this topic in my ebook.
Part 3: What new law would you introduce to improve life in your country?
Advice: Choose an easy topic like "environment". Explain that the government could introduce new laws to reduce pollution from factories, cars etc. Explain how this would improve people's lives.