Skimming
Skimming is reading fast to get the "gist" or the general idea of the text. There are different techniques of doing skimming. You can run your eyes over the text getting the general meaning, not stopping at words that you don't understand as this will slow you down. The important thing with skimming is speed. Another way to skim is to just read the first and last paragraphs of a text and summaries as well. You could also just read the title, subtitles and illustrations if there are any. I prefer for IELTS the first way - reading it all quickly to get the general meaning, but of course it depends on your reading speed. If you are a slow reader in English you really need to practise to improve. You don't need IELTS specific texts for this. A good English newspaper is fine. Get one every day and read the articles as quickly as you can. Do this with as many articles as possible every day and your speed will quickly improve. Using IELTS practice tests is of course the best way to practice.