The first 10 questions of the Chinese HSK6 reading section are notoriously hard. Each question gives you 4 sentences and the task is to choose the one containing some kind of error.
This part is so hard that it's common advice to blindly guess in order to save precious time for the other questions: i.e., just choose option "b" for all answers, giving 25% chance of getting it correct. It's difficult for native Chinese speakers who are reported as commonly scoring at most 7-8 out of 10, and even difficult for Chinese teachers.
It is argued that if someone is able to answer these questions, their Chinese is already so phenomenal they won't be taking the HSK6.
Indeed, my experience with practice questions is that if I make a genuine attempt at the 语病 section, despite spending far more than the allocated time, I consistently score worse than 25% (i.e., I'd probably get a better mark via guessing, while simultaneously saving time for other questions). On one practice test, I even utilized the Internet for help, looking up every unknown word and its grammar patterns; this took over two hours, and I still scored 2 out of 10 (which was rather demotivating). I feel like many of the sentences are "trappy": they use unfamiliar collocations, grammar, etc., but are technically correct.
Maybe there is some technique I'm unaware of...
Question: For those who didn't blindly guess on the notoriously hard HSK6 语病 section, how did you prepare?