In Part 3 of the IELTS Speaking test, you will be asked a few discussion-type questions. To get Band 7 or higher, you need to use a good range of vocabulary, linking words and phrases (I would say, as I said, etc.), a variety of simple and more complex grammar structures and clear pronunciation. To get Band 7, you can make a few more mistakes compared with higher bands. Check out this Band 7 sample answer from the IELTS official YouTube channel.
This will give you a good idea of what you need to do to achieve your target band.