Maybe practice will help you raise your scores. Otherwise there are a couple of different methods, Outline, Search and destrpy. Use whatever works best for you. This section though is really a more of either you got it or you dont.
worst come worst, score high in all other sections to mask the poor RC score. I didn't plan on doing that on my DAT but still managed to get in to my school of choice.
Hopefully you get lucky and get some kickass passages.