Perhaps the magazine has worked for you, but I find the economist to be very soft reading material and unsatisfactory for RC improvement. For a food analogy, It's like chewing Gerber baby food, when RC passages are like tough sinewy steak.
However, I will say that what seems to work for me is reading philosophy books, in particular books by Daniel dennett. I'm currently reading his book Intuition Pumps, and after reading a few chapters of it, when I do rc passes, I feel myself breezing through them. (I know he's most famous as a new atheist, but his philosophical insights are his most impressive contributions to thought in my opinion).
If you're struggling with RC give him a try. Freedom Evolves, Brainstorms, etc. He has many books from decades of writing. Also, consider that every lsat question you've ever read was written by someone who was either a philosophy PhD or in pursuit of a philosophy phd. The two subjects , LSAT and philosophy, seem to be almost the same thing. Best luck to all, keep studying!