How to Solve SAT Reading Big Picture and Inference Questions?

I'm shooting for a score above 750 on the SAT Critical Reading section, but I've been consistently scoring in the high 600s because I have difficulty on big picture and inference questions. I can usually narrow the choices down to two or three possibilities, but I have trouble eliminating the last one or two incorrect answers. What am I doing wrong? How can I fix this issue?

The best advice for fixing this problem is to remember that there must be direct evidence for your answer in the text (even when the question asks you to make an inference). If you have to make any assumptions that aren't based on direct textual evidence, the answer is wrong. All answers to SAT Critical Reading questions must be objectively true; otherwise, the test would lose its viability as a standardized measurement of critical reading ability. Read this article for a more detailed summary of this fundamental rule:

I would also advise you to continue practicing with difficult Critical Reading questions so you can become more familiar with how the test might try to trick you. Here are some of the most difficult SAT Critical Reading questions with helpful explanations of their answers: