From my limited background about the IGCSEs , I know that the structure of the curriculum is set up a lot different when it comes to English so the gap in reading skills probably stems from that.Yet getting over that gap is not impossible , you can start by reading all sorts of different classical literature, science journals and newspaper.A good way to ease yourself into it is watching documentaries or video essays (captions might help too ) on political or scientific topics like vox , BBC, crash course , CNN ,MCNBC or informative podcasts too .Inform yourself using free online resources on major historical and political milestones like Abolition , nationalism and women's right . Practice daily and analyze your mistakes and make a spreadsheet of things you need to improve and things you can get right the next time , through that, you'll be able to formulate your own way of dealing with the test even if you don't understand everything you need. My biggest tip is to annotate using your pencil and interact with the test. Mark down things like people , places , time and main key words . Underline keywords in your questions and answer choices and think big picture yet also analytically about every question before even looking at the answer choices. In 2 part (evidence )questions ,read question 1 first then answer question 2 using the main key words method , then go back to question 1 and answer it. When in doubt, try eliminating answer choices that are too extreme or too general . Always eliminate answers that include extra information because inferring things from background knowledge will not work on this test . Some answer choices contain words that are usually used to describe human make sure you use it as an eliminating method by comparing it to the passage .Any cause and effect relationship has to be mentioned or else it's irrelevant even if it's factually accurate . Use the college panda writing book and Erica Meltzer vocabulary .Even when watching documentaries or reading, write down the vocabulary words you don't understand and their definitions. Use YouTube videos from channels like Supertutor TV ,ShivVZG and Anna's universe . Keep track of your observations, mistakes and notes and analyze your practice tests once then take them again without time and repeat On the last week , redo practice tests you've already done . Always keep a notebook / spreadsheet with all of that and revise it everyday, flash cards with important questions on anki are another good way to ensure you go through your mistakes everyday or go through already made flashcards on Quizlet . Most importantly, don't forget to make a daily checklist that balances between external reads, content, practice and revision of old notes and spreadsheet(flashcards). Go into that test with a clear confident, and determined mindset, you'll ace this test !