The writing section of the test is incredibly teachable: learn to do a few simple tricks, and you can boost your score by hundreds of points. Reading is a different beast entirely. Because it requires you to untangle the meanings of complicated sentences, you have to know the meanings of words that constitute those sentences, not just their grammatical status.
So I have bad news: you probably need to study vocabulary. If you are an avowed reader who tirelessly treks through mountains of books every year, congratulations, this advice probably isn’t true. I barely glanced at vocab lists before diving into the SAT, and I was somehow able to score a perfect 800 on the Critical Reading section. But I was also reading scholarly analyses of T.S. Eliot’s poetry during driving school in tenth grade. You were not. Trust me: study a vocabulary list. The most efficient one is the Direct Hits series.
You could also try to read some Modernist poetry. Or even some non-Modernist poetry. Just read. See the words that you learn on the lists in the wild, roaming free on the pale savannas in your book. Identify them there. Tag them and remember their meaning. The next time you stumble upon one, you will recognize it more readily. Eventually, you’ll have your own private menagerie of exotic words.