My informal poll left me with the impression that it's not easy to move a Critical Reading score.
Daniel Willingham says Critical Reading strategies can help, but are more of a trick than a skill.
That said, I had a game changing meeting with Erica Meltzer the other day and will be following this up with a post about the strategies she taught me, which I passed on to my son who was very appreciative and said it made that section much better.
In the meantime, you can read her post about How to Study for SAT Critical Reading.
(Cross Posted on Perfect Score Project)