Don't memorise answers, especially in Part 1. Memorised language doesn't give the examiner an accurate measure of your English-language skills.
You may want to impress the examiner with big and complex words in your Speaking test. But to be safe, avoid using words you are not familiar with.
Try and use a range of grammatical structures using complex and simple sentences to express what you want to say.
With a face-to-face Speaking test, the IELTS examiner understands a wide range of accents so will be able to understand what you say, unlike an AI machine.
There is no harm in taking a brief pause to think about what to say. We all do it to process questions. You can use phrases to give you time to think during the Speaking test
Speak confidently and avoid using filler words. We generally use fillers when we don't know what to say, however, this shows the examiner that you can't access the appropriate language or ideas
Try and answer the examiner's questions in full. Extend your answers and don't wait for the examiner to prompt you with a question.