How to improve CR & RC

For CR I find that the most important thing is identifying the conclusion for the strengthen/weaken/assume questions. Once you get this then you have to "dump it down" and pick the only answer which directly relates to the conclusion. I find that a lot of errors are because I assume too much. Same idea for inferrence questions, find the conclusion which doesn't go beyond the given premises. And then for the mimic the reasoning, sometimes I will make a few quick notes to understand the logic structure.

For RC, there are so many ways out there from readuing the entire passage while taking notes to skimming the first and last sentence, etc. I like to read the entire passage pretty carefully (but this takes me about 2.5-2.75 minutes which is pretty good timing IMO). Then when I get the general questions, I usually can pick out the right answer and if I can't, I go to the first and last sentence of each paragraph and skim quickly to get the overall gist. And for the specific question, you need to go back to the passage and eliminate each answer choice. Look a little above and a little below the answer choice to make sure it follow the same tone.

For RC's author's tone, MGMAT says that all these articles are published so the author will never be too far on one side (overly supportive/critical) and will be somewhere in the middle. So you normally can eliminate the extreme answers and then pick between the slightly optimisitc, cautiously optimistic, valuable but problematic, etc.

Other than that, practice practice practice. Good luck!