The English reading section is a time problem before it is a comprehension problem. Students who understand every word but read every word twice run out of clock.
For each passage, spend twenty seconds on the first and last sentence of every paragraph. That gives you the argument's skeleton. Now read the questions and only re-read the passage in the specific places you need.
For 'main idea' questions, the answer is almost always paraphrased from the first or last paragraph. If a candidate answer is a paraphrase of a middle-paragraph detail, it is a distractor.
For inference questions, be conservative: the right answer is only mildly beyond what the passage said. If a candidate answer is a huge leap, it is wrong even if it sounds insightful.
Vocabulary-in-context questions: substitute the candidate word into the original sentence and see if the sentence still makes sense in the passage's argument. Do not rely on your dictionary definition.