Speed on CR question.

I had the same issue. Two things really helped:

1) Always keep the GOAL in mind. Goal = Weaken/strengthen/evaluate the conclusion OR focusing on how the author came to conclusion in assumption questions. Remember the key is to understand the argument (read slowly), focus on EVERY WORD of the conclusion, pre-think some scenarios if you can, and then move on to the answer choices. I realized that I didn't have a deep understanding of the argument, and never had the goal in mind, leading to incorrect answer and 3+ minutes. That extra time is spent on going back to conclusion/argument and coming back to answer choices. I repeat again - "focus on the conclusion".

2) Pattern recognition. This also helps a lot. I'd suggest that you do a thorough analysis of every CR question and start recognizing patterns. I did this on OG questions and started grouping the GMAT prep questions into these different patterns. Of course its time consuming and you don't have to do this for every question, but knowing some pattern improves your speed. This is also stated in the Powerscore CR.

I'd suggest you go through Powerscore CR once and solve every question. It will train you to focus on the conclusion, argument leaps, new word in the conclusion, etc., which will help you improve quickly. I had a very low score in CR in my first attempt, but after doing all the above my CR jumped drastically in the second attempt. Powerscore is highly recommended.

Good luck!!