Your vocabulary is too small now. IELTS 6.5 is not only a vocabulary, but also a bare back. I studied IELTS for a month and got 6. My vocabulary is around 7000, and my foundation is not bad. High school 150 points 120 points, for reference only. You have two years to prepare, and you can recite one hundred words or fifty words every day. If you recite too many words a day, you will forget them. You can recite the red book or the green book. As for English books, the ten-day series of cautious oral writing is good, and Lu's can also be used for listening. You can buy Lu Wang's vocabulary books on listening and writing, and then read them, so that you can get 9 points. Reading depends on practice. Of course, you can do IELTS series 4-8 several times, and you can get a nine this year. Recite the words you don't understand in the article after each reading. That's about it. I hope I can help you.