In your articles, you have greatly emphasized on reviewing our mistakes after doing every practice test. I applied this strategy and improved my score by 110 points in just 15 days!
In Math and Reading section, I found it quite easy to review the but as far as the reading section is concerned, in all of my wrong questions, the only mistake I find is that I was not able to comprehend the passage. Could you please tell me that is this a right way or am I doing it wrong?
Do you not understand just small parts of the passage (e.g. a hard word, or some small part of the sentence), or do you not understand the overall meaning of the passage? I'm going to guess you don't understand the passage overall -- we call this skill understanding the big picture.
If you use a customize product like PrepScholar New SAT prep, we will actually find out what the issue is, and we have lots of drills to fix your big-picture passage issues. That's exactly the use case of our program.
Overall, as a fundamental skill, the best way to build up to this level of reading comprehension is to read more and more difficult books or short stories. For example, take a look at this list:
http://www.ala.org/alsc/2016-summer-reading-list
and for short passages go here:
http://englishforeveryone.org/Topics/Reading-Comprehension.htm
Start with easy reading, but make sure you know 100% of it. All the words, and every single possible explicit and implicit (in other words, hidden) meaning there. Who was the author? What was the point BEYOND what was written down?
One of the best ways to improve on this is practice/