Okay, I'm assuming your test is now in probably about a week, so obviously there isn't much you can do (and hopefully things have improved!) but here's what I'll say (from someone also taking the test in about a week)
Psych/Soc: Just find a way to cram definitions. Make your own Anki cards or use a prebuilt deck, read through a compilation, anything like that. Look at your old tests and check every P/S question - what terms (specifically in the answer choices) do you not know the definition for? Make a flashcard or look up a definition. If you do this for a few tests worth of passages you'll have a pretty decent idea of what topics you'll be confronted with. There is definitely critical thinking in reading the passages but that's not possible without the definitions, and some questions are freebies if you know the definitions (especially if you eliminate choices)
CARS: I feel like the majority of errors you can make in cars are either missing something in the passage (skimmed over or misread) or errors of "extrapolation", and I think the second is more common. The right answer is rarely the one that looks "superficially" correct. You have to actually think about the relationship described. Maybe a passage is talking about a plumber, and what it's like to work with pipes, and then it'll ask you "Which job is most similar to that of being a plumber as described in the passage?" and then the answer will end up being cardiologist, because they wanted you thinking about pipes. The easiest error to make here is pick the answer that says "construction worker", or something like that, because you were focused on the superficial.
CARS wants you to behave as if you have no outside knowledge of the subject. It's easier, in my experience, to mess up on a passage you know about because you're going to start inferring things, making reasonable, calculated judgements and guesses, but they expect you to do this and will have answers to "trap" you if you start drifting away from what the passage actually says.
I think if anything would be able to make noticeable, maaybe a few points, differents it's these two things. But just my opinion!
Good luck on your test!
