To improve on the reading comprehension section, get your hands on academic journals, scientific studies, art criticism, the editorial sections of major newspapers, magazines like Foreign Policy and the New Yorker.  Also try to figure out your areas of weakness and look for reading materials in those areas.  First, start reading the articles or publications slowly to understand what you are reading.  Then gradually increase your reading speed as you get more comfortable understanding the concepts.

Second, get your hands on real test questions and do as many test questions as possible.  When doing the reading comprehension questions, identify the conclusion of the reading segment of the question and select the answer that impacts the conclusion the most.