I recommend doing daily passages from Jack Westin (
Jack Westin) and reading a variety of longform articles online (
Longreads : The best longform stories on the web). The daily passages will help with the structure of the exam and the long form articles will help with reading comprehension - make sure to read through topics that DO NOT interest you.
If you haven't done the AAMC practice material (question banks, full-length practice tests), do try and knock them out. CARS is hard, but with practice you can improve your score.