I sucked big time until a few weeks/months ago. I feel a lot better with RC these days.
Try this book if you want to
https://www.amazon.com/Read-Better-Faste ... 0690015283Has some pretty good stuff. Here are some key elements for improvement in RC
(1) Short passages 2-2.5 min and Long ones with 3-3.5 min with good comprehension ( if we just read no use) Book by N L helps you to increase speed while comprehending better.
(2) First focus on getting the answers right, then once you are getting answers right focus on reducing the time. Time in RC for non native speakers should come into picture only after they get accuracy. Just my opinion.
(3) Eliminate Half right Half wrong answers.
(4) Apply principle of locality extensively. Do not bring any thing into the mind that you dont see in the passage. This will really make you see why 2/3 choices are wrong outright.
(5) For main/primary purpose or author's attitude avoid strong word answers. Concentrate on the verb in the main purpose answer choices and then verify that the whole sentence is inline with the passage's main purpose. Some times GMAT will change some thing in the middle or end of the sentence and that makes the answer correct.
(6) Follow the 7 principles
MGMAT says. Just enforce them. Discipline is the key. Its tough to do so but you will get there.
I know I have still some stuff to get a better grip. But I feel a lot better.