Have you been following along with your course BigRed? I found a combination of doing the course and also practice questions both from the course and the books they sent to be the most useful for me.

I found that reading articles and texts from a variety of sources helped my daughter. Her tutor had her read 3-4 magazine, newspaper, opinion articles, or SAT passages a week and practice understanding them by writing a short outline. She would write out the main point, the details and arguments used to support the point, and the attitude of the author (e.g. what were the author's emotions like? how did he/she feel about the subject) This was a really good method to help her become confident in her critical reading abilities in general.