I looked at a copy of Barron's once and found that it was not quite up to the standard of some of the better material. It would be a good idea for you to get the Official Guide 12th Edition along with some good material from a top company. People have their favorite books (I contributed to the Veritas Critical Reasoning books so I am biased in favor of those...)
Whatever materials you decide to use, do check back here tomorrow, I will be posting an end of the year listing of some of my critical reasoning explanations that may help you to develop techniques to approach each type of critical reasoning question. I think you will find the sample questions, explanations and techniques useful.
