Reading authentic texts can help, and so too can doing practice reading tests, but trying to boost your reading score this way takes many months, if not years.
The quickest way to improve your IELTS reading band score is to learn the many hundreds of difficult words that are found in IELTS reading tests.
Luckily, there are books designed to help you do just that!
An excellent example is Barron’s 600 Essential Words for the IELTS.
The book contains 10 units, each with 3 passages centered around a single theme.
Each passage contains 20 essential words and revision activities to help you remember them.
That’s 10 units x 3 passages x 20 words = 600 words
Here are the 10 units:
It’s possible to study one passage a day, which would allow you to complete the book in 30 days.
This book is available for as little as $31.71 HKD from Amazon:
Essential Words for the IELTS: With Downloadable Audio (Barron’s Test Prep) Third Edition