Hi there,
I'm not sure if you got the answers you're looking for but here are a few things I can suggest:
When reading the passage:
-are you keeping aspects such as the topic, tone, scope, purpose, and structure in the back of your mind when reading? You won't have time to jot these down but it's still important to focus on getting these components out of the passage when you are reading.
-try to imagine it's a friend telling you a story as you read. This can help you focus on the overall thesis or gist rather than the details.
-Often there are "hotspots" which tend to contain the ideas that compose the main idea of the passage. While there is no secret formula and each passage is different, it may help to take particular note of what is said in the opening paragraph, last paragraph, and the first or concluding sentences of each paragraph.
-Focus on the author - who are they? What are they trying to convey to the audience?
After you read the passage:
Try to answer the questions such as the following in your head before writing out your main idea sentence:
-What is this passage about (the topic)?
-What is the most important thing the author says about the topic (the main idea)?
-Do all of the other ideas in the passage support this main idea?
When answering questions:
-keep the main idea that you've just constructed in your head when answering the questions, but don't forget to use elimination as well
-watch out for distracters - if you say you're getting caught up in the details, you might be selecting answers that are too narrow and only focus on a part of the passage rather than the overarching theme.
Without knowing exactly what strategies you've tried and what you're finding most difficult (running out of time, the types of questions or reasons you're getting questions wrong) it's difficult to provide more specific advice but hope that helps a bit. One of the most valuable things you can do as a practise strategy is to spend time going back and analyzing old exams you've written. In particular trying to determine why you got the questions wrong that you did can be a big eye-opener in how to improve your score.
Hope that helps and good luck!
Tania