You need to work through a number of practice tests in order to identify exactly what you need to do and to understand how to correctly answer each type of question. After doing a few tests, analyze your answers. Doing so will help you recognize which types of questions are easier for you and which types cause more difficulty. Consult your teachers or specialized IELTS guidebooks to learn strategies to help you with ones that are more challenging.
To do well in the IELTS reading test, you need global as well as macro reading skills. This means you should to be able to do the following :
Specifically, three key reading skills will help you do the above most effectively :
The first two strategies, skimming and scanning, involve reading very quickly, but each strategy has a different purpose. Skimming means reading quickly to get the main idea of a text. Scanning means reading quickly to look for a specific piece of info or specific words. The third approach, reading for detail means reading every word in order to really understand the message of the text.
On the IELTS, you will need to use all three techniques at different stages. For example, you may start by skimming through the entire text to get a general idea of the passage. Next, you may look at the questions to see what kind of information is required. Then, you may scan the text for a specific piece of information or read a particular section in greater detail to discover the information you need to answer the question correctly.
If you are weak in these areas or read slowly, there are a number of excellent general ESL and specific IELTS books which can help you strengthen your reading techniques, so you can complete the test correctly and successfully within the one hour time limit.