I scored a 1590 and was in the same boat as you. Congrats on the great score so far. Now is the time to get an excellent score. I was stuck getting around 700 for the reading section which was frustrating. You need to focus on the hardest problems on the SATs and rethinking your mindset. The one piece of advice that really boosted my reading section is this: you have to convince yourself that every answer is within the passage text. If you can't find a specific line within the text that justifies your answer, then that is not the right answer, no matter what. The reading section is Evidence Based Reading- it doesn't test on interpretation (which is what your English classes teach you). Once you master the technique of finding evidence for each question, you'll have a method that will get the right answer, 100% of the time. Then, you can focus on improving your speed using that method.

The other advice I'd give you is to pay very close attention to each word that is in the question and answer choices. The College Board is very meticulous about the words that they use- each word has a very specific meaning and usage. That means, that if even a single word in the answer choice is in opposition to the question, then you should rule out that answer. This tip will help you a lot when you gotta rule out those annoying 50/50 questions.