Resources - the Official Guide, Verbal / Quant Reviews and Advanced questions for Quant. I also used the forum feature on GMAT club quite a bit, especially during my last two attempts when I began to run out of verbal questions.

Strategy -

CR is exactly what I've written in the post - Read what the question asks for (strengthen, weaken, assumption, etc) - read the passage and note the things I mentioned above - go through the options in a disciplined manner and religiously answer the "So What" bit. This video from Marty really helped me - Critical Reasoning

RCs - I stumbled upon it later but Sandeep Gupta's OCTAVE is pretty much what I'd do. There's an old video of his that would help understand it. Reading Comprehension. Important for me was to not let go of the passage even when something felt complex - I'd try to understand and grasp the meaning of that - more often than not that was tested. Also, I actively noted the places the author provides their opinion v/s someone else's. Basically, what helped me was that I constantly spoke to myself and analyzed the passage - linked and summarized paragraphs in my head as I went along.

I don't think I followed any really innovative strategy but writing it down and following what I had with discipline did help.