To begin, no matter what I do, unless the questions is super easy, I cannot identify what is necessary for a conclusion to be true. I've tried finding a stategy that works for me, but nothing is clicking.

Common suggestions that don't work and why:

Negation technique - Even if I negate something and say it's not true, when I look back at the stimulus the conclusion no longer seems wholeheartedly sound. But it ends up being wrong all the time. Even if I negate something, I cannot identify why it's necessary or not.

Must be True - I suck at MBT questions, but even those are easier than NA's. But again, for the same reason as above, I can't look at a question and identify what is necessary for the argument to be true.

Identify the Gap - Most of the time I ask myself, why does P-> C, which I know is used for Sufficent questions, but it's the only stategy that actually feels like a stategy. But I can't identify a gap or flaw in the logic, becuase 9/10 I'm wrong.

Is there any other stategy to tackling these questions than using the negation technique that could help me identify what is necessary for an argument to take place?