First of all, the necessary "Cambridge 1-6 IELTS test analysis". At present 1 and 2 may be too old, so you can start with 3. 5 and 6 are the latest, close to the actual IELTS test and should be completed before the exam.

Other materials, such as black eyes and IELTS practice plus.

I want to talk about reading in IELTS reading truth. Personally, I feel that IELTS is more rigorous and other materials are not necessarily so good. So when reading, you may get good grades in the Cambridge series, while when doing other materials, your mistakes will increase greatly, and the feeling of doing problems will get worse. You even think that some problems are difficult and ambiguous, and you can't work out the whole problem. This is because other materials are not so rigorous and are not well made. Don't worry too much.

The writing reference book "10 Breaking IELTS Writing in Days" is quite good.

Spoken language "10 days to break through IELTS speaking" and so on. There are a lot of oral materials, you can just find one set casually, as long as you read all the questions yourself. There is not much information, but you can read it carefully from beginning to end and improve it.