if you were to read each of these passages, word for word, you spend nearly 30 minutes. Hence, we advise to skim through the passage.
Some students, in order to save time, start answering questions directly. Well, this is as bad as reading the entire passage. Of course you might save time, but, quite possibly your answers could be wrong.
Any more than two words and you defeat the very purpose of the question which is to test your vocabulary and paraphrasing ability.
If you are not familiar with the types of questions asked in the reading test of IELTS, you might spend a few valuable minutes of your test duration, just to understand them well.
If you do not manage your time well, you make it simply impossible. Answer the questions that require less brainstorming before the complex ones. Eliminate options from multiple choice questions before you actually search for the answer.