Yeah the reading comprehension is somewhat particular. The basic thing to remember with it is that you need to train yourself to read for structure, not content - though judging by your scores I'd guess you're doing that to some extent, at least intuitively. Before giving some specific advice there's one thing I suggest to all of my students in terms of long-term preparation. You should definitely take the time to read something dense and challenging on a daily basis, but I respectfully disagree with those who suggest that that includes magazines or newspapers like the WSJ, the Economist, the NYT, etc. As sophisticated as that might be the main problem with magazines and newspapers is that they're designed for a somewhat generalized audience and they're designed to be read for content. Instead what I've found helps my students a lot is reading from the following book: A Companion to Philosophy of Law and Legal Theory
. Reading a section at a time can be very useful if you've got months to go before the test.
Other than that, I teach my students what I've termed the POTS
P = Perspective
O = Oppositions
T = Tone
S = Structure
Each passage is going to have several different perspectives or points of view about a particular subject matter. These perspectives are generally going to be in opposition or conflict with one another and the author's tone or word choice will articulate their evaluation. The structure is a manifestation of these three other things in the paragraph as a whole. I find that this is a conceptual framework that has really helped my students map out and understand the passage as they're going through it.