Exam

First study NCRT books, they are suitable for this preparation.

I think you should opt for TIMES. It's a best coaching class for any entrance.

For English reading comprehension consists of 50% + paper. Always read only one para and write down in 2 lines simply what u understood about it. Do this for all 3-4 remaining paragraphs for 1 complete paraphrase. I will get the best gist of the comprehension.

Common Admission Test (CAT) 2017 will be conducted on November 26, 2017 in two sessions. Registrations for the exam for entry into the prestigious IIMs and other B- schools will open on August 9 2017 and will close on September 20, 2017.
This year, IIM Lucknow will be organising CAT.

Yes, you can but you need to clear your backlogs before the completion of 4th year of your BE degree.

Kindly visit the URL:-
http://www.nmat.org.in/about-the-nmat/why-take-the-nmat/

Hello Akash,
As you mentioned that you are in your 4th semester, so technically you have enough time to prepare for CAT.
Some of the offline renowned institutes for CAT preparation are Career Launcher, IMS and T.I.M.E.
Online classroom sites:
Oliveboard
Handa ka Funda