Time management is very much important in IIT JAM. The eduncle test series for IIT JAM Mathematical Statistics helped me a lot in this portion. I am very thankful to the test series I bought from eduncle.
Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
Deb dulal halder Halder
these materials are good and comprehensive for the course, but won't suffice for the NET EXAM. you will need to read much more extra. let me know the topic, you doing, I can suggest you the books to be consulted.