You nust focus on important topics and solve as many sample papers as you can to improve speed and accuracy. 

Analysis of weak zones and revising them is key. Try to solve sectuonal mocks if you are weak in particular section . All tips sharedbelow. 

https://design.careers360.com/articles/how-crack-nift-entrance

For Gk you nust refer to daily newspaper snd Manorama Year book and Lucene GK Book.

List of all recommended books below. 

https://design.careers360.com/articles/nift-2019