that's a good question. i don't have an answer but i can try to get the ball rolling. hopefully we'll have a good idea by the end of this thread hehe
i guess i would say the approach obviously depends on the type of question. For big picture questions (purpose, attitude, main point, purpose of paragraph) it's a bit easier to correct for it. Did you miss a huge chunk of the structure in the answer you chose? was your answer too narrow or broad? for big picture a lot of times this is the problem (at least for me) because i choose an answer that misses something (broad) or choose an answer that misses something important (narrow). then you take this and you adjust for how you read, perhaps focusing on the structure, not getting bogged down in content.
for specific references, why you got it wrong was obvious: you either didn't remember it correctly; or when you went back to search for it you couldn't find it and guessed or misunderstood once you read it quickly. so getting these wrong just tells you that you need to find a better way of tackling specific reference questions. maybe you should make a mental note after each paragraph summarazing what you just read so that you know where things are. maybe you wanna try reading specific references questions first (i don't recommend this necessarily, but i think it's worth trying for a couple of passages to see if it works for you). i think those are the only two methods i know for tackling specific reference questions.