Here are the key skills involved:
1) Care!
Engage with the passage. Don't tell yourself it's boring. On the contrary, cultivate your curiosity on the topic. There must be some element of mystery or debate here, some bit of knowledge to explore. Pretend you are friends with the author and earnestly want to know what they are talking about, even if you aren't able to follow every last bit. Treat
every passage this way, regardless of its content. If you find some passage types hard to engage with, spend extra time in that field to get more comfortable.
2) Read the passage efficiently for main point and structure.
Your goal should be to identify the author's point and then relate each paragraph to that point. What is each paragraph basically saying, and how does that connect to the author's overall point? What you
don't need to do is understand every single concept or memorize the details. You should get through the passage in 2-4 minutes, depending on the content and your reading speed. (Most people read too fast, not too slow!)
3) Read the question and prephrase an answer.
Most questions can be answered to at least some extent in advance. What is the question asking about and where does the passage provide an answer? Some answers are harder to predict than others (for instance, maybe the question simply asks "Which of the following statements would the author be most likely to agree with?"), but you should typically have at least some idea of what a good answer should look like before you look at the answers.
4) Work the answers carefully.
For each answer, can you definitively say yes or no? If not, leave it for now and move on. If you get to an answer that matches what you're looking for, just look through the answers to make sure there's nothing equally tempting. if you're left with several answers, compare each back to the text. If they all seem to match, compare them to each other. What subtle differences are there that you can narrow down?
5) Master the art of inference.
Sometimes the question wants you to identify what the passage implies or suggests. What are they looking for here? It should still be something that you basically know from reading the passage. It just might require you to combine two or more statements, or to make a common-sense inference. (E.g. If China banned imports of a certain product, then not all markets are open to that product.) An inference is not an intuitive leap or a test of outside knowledge.
Those are the big things. Do you have a sense of which elements are toughest for you? When things go wrong, where do they go wrong? I'm happy to give more specific advice.