Infact CARS section of MCAT examine your thee main skills
1. How would you understand the basic component of the text which define your foundations of comprehension.
2. How you evaluate the arguments and evidences shown to you which defines your reasoning with text.
3. How you define react and apply the information to the new scenerios and contexts which actually defines your level of reasoning beyond the text you see in the paper.
So you make sure you are well prepared as above, you need to have diverse critical readings and simulated practice tests that can highlight you weak areas and make sure you are up to the mark as you have to read 9 passages to answer 53 questions within 90 minutes.
> First of all read AAMC official documents
> then practice test at examoo free mock tests and also read and check Khan Academy MCAT study materials.
Remember, the more you practice the more you would better at your exams.