I would not probably make this suggestion for any topic other than Critical Reasoning and Reading Comprehension, but have you tried some official GMAT critical reasoning questions?
Before you start to make things overly complicated (which the Powerscore Bible book will certainly do) try some questions. Critical reasoning does not require any special rules or formulas, just read the stimulus and try to answer the questions and see how it goes.
If it does not go as well as you would like, the problem is likely your focus. In other words, you may not know exactly what to focus on in the stimulus and in the answer choices.
At Veritas we do break the questions down into the big question types like Strengthen, Weaken, Assumption, Inference, Paradox, Plan, Bold-faced, and Most Useful to know (in order to Evaluate).
Yet the reason that we break those questions down into categories is to help you to place your focus.
For example, the Inference type of question has more of an emphasis on the answer choices. The correct answer "must be true" based on the information in the stimulus. On the other hand for a strengthen question the emphasis is on the conclusion and what I call the MIP (see the article below).
My advice is to keep it simple first so don't start with PowerScore Bible. And whatever material you are using PLEASE view it through this lens:
You have all of the intellect and all of the tools necessary to answer any Critical Reasoning question. The books that you use to learn CR should help you to know where to place your FOCUS. That is all that you really need from them.
Just to help you get started here are three articles that talk about where to place your focus for strengthen questions and Plan questions and on how to see critical reasoning like an expert does:
https://www.beatthegmat.com/mba/2011/02/ ... duncan-way
https://www.veritasprep.com/blog/2013/0 ... an-expert/
https://www.businessweek.com/articles/20 ... -questions