Reading is the hardest skill to improve quickly because it depends on reading speed and vocabulary and neither can be improved quickly. Here are three things to do in relation to the reading test.
  1. On the test day, spend only 20 minutes on each reading task. If you don't finish all the questions in one section, which is very likely, guess the ones you didn't get time to do and move on to the next section. Easy strategy: 20 minutes MAXIMUM on each section.

  2. Practice improving your ability to skim quickly through a reading passage but still get from it the main points. Do this by taking a passage that is about 200 words long (about 13cm in the Bangkok Post or Nation, I think) and giving yourself 1 minute to skim through it and try to pick out the main points.
    You will need to skim in the IELTS exam at a speed of about 200 words per minute. This will give you 4 minutes to skim a passage before starting in on the questions. Very often, you can read the first and last sentence of a paragraph and have a pretty good idea about what the paragraph is about, without having to read all of it. While this works most of the time, you must be careful that the middle section actually does support what the first and last sentence lead you to believe.
    This needs daily practice. It is time consuming but it isn't hard. After you have skimmed the passage, you must go back and read it very carefully to check that what you thought it was about was, in fact, correct.

  3. Expanding vocabulary. Some people might find this boring, but it is unbelievably important.
    'Google' the "General Service List" - the 2000 most common words in English. You will know many of these, you should know them all.
    'Google' the "Academic Word List" - this is a list of about 550 words divided into 10 groups of most common to least common. These are words you will likely read in IELTS reading and they are words you should be able to use in your own writing. Some Thai universities are using this list to determine the vocabulary skill of their students in Academic English classes.
    Research shows that readers need to understand almost 95% of the words in a passage to have a good chance of understand clearly what the passage is about. This is way higher than English teachers had believed in the past and has very clear implications for what English learners must do about learning vocabulary.