In my attempt to increase my verbal score from a low V31 to a moderate V40, I have decided to focus on acing the SC section given that that section is the easiest to improve. I tend to have around a 75% accuracy on 500-level and 600-level problems. However, my accuracy on 700-level problems is about 40%. On these difficult problems, I can't really find a split in the answer choices and the correct answer choice tends to be based on some obscure grammar rule that is not repeated in other problems or some subtle meaning difference.
I know that Ron has said time and time again that the difficulty of the problems is not that important, but I strongly disagree, because I have seen that 700-level problems are extremely different from 500-level problems. I have seen that SC errors in 500-level are glaringly obvious, but those on 700-level can pass under the radar of the even the best test-takers.
What is the most effective way to prepare and ace the most difficult SC problems? Please note that I do let the meaning of the sentence guide my thought process.