Your post makes me think that you may need some more practice with the English language to boost your understanding and reading speed before working on CR skills. I suggest trying to make English part of your daily routine, by reading high quality materials, such as a good book or reputed newspapers, like The Economist or The Wall Street Journal.

The CR bible is truly a great source for strategies concerning CR. Merely reading it will not suffice: you will also need to carefully review the concepts and try to memorize some of their tips.