I recently stumbled upon this interesting website where you can find videos about several subjects, from biology to economics. There are series of videos course-like from respectable professors of top universities.
They also have a section for test preparation:http://www.academicearth.org/subjects/test-prep
They have 54 videos on Problem Solving. The person reads the question and solves the problem writing down every step so you can actually watch it. It's based on the OG 12
, and includes 249 problems.http://www.academicearth.org/courses/gm ... em-solving
They also have 41 videos on Data Sufficiency, totaling 155 problems.
I think it's a valuable resource, I have watched just a couple of the videos and they look ok. If you are in a stage in your preparation where you can't get your eyes and mind on the book, I think it's worthy to try watching a video.
I hope you find the website interesting!