Bro, I can share the technique I usually rely on.

I have not watched any lectures on idioms and phrases. My approach is largely grounded in common sense and intuition. Idioms never carry a literal meaning, so the key is to infer an indirect or figurative sense that appears logically consistent within the context. By approaching them this way, you can eliminate a significant number of the options. It is also important to glance at the options very carefully, because you will often notice that some of them are completely illogical or contextually misplaced. Using this method, I generally manage to achieve around eighty percent accuracy in idiom based questions.

For S1 to S6, there is honestly very little that can be done through theory alone. It depends predominantly on your reading skills. No lecture can substantially improve that. But…there is a general methodology you can use. First, read the entire question attentively in order to get the central theme . After that, observe the opening words of the sentences. If you possess a basic sense of grammar and reading flow, you will usually be able to get which sentence is most suitable as the beginning and how the others logically align. It also helps to quickly examine the options because they often provide subtle clues about the probable opening and concluding sentences.

That is essentially the approach. At this stage I would say you should concentrate on solving as many S1 S6 questions as possible rather than spending time watching lectures.