Cracking NIFT is not at all difficult. You just need to know the basics which we are well taught at school and in general. General Maths and logics. General Knowledge questions which need not be just bookish knowledge but really common ones. Like “Who is the host of show Satymev Jayte?” or “Who is the brand ambassador of the brand FLITE (footwear)?”
Apart from that, you should have drawing skills too. Not like major ones but you should be able to draw and illustrate what is asked for. Sometimes poor drawings lead to less/no understanding of what you’re trying to depict. So be clear. Neat. Do not smudge eraser a bit too much.
The second level is all about creativity. Few topics are given to you where you have to make a 3D model on any one of the topic in two hours. They provide you with materials and everything.
That’s it! Do not fall prey into going about preparing at any coaching or somewhere. Imagine they “train” people to be creative. That’s false. Creativity is from the inside. How on Earth would you be unique if your minds are trained in a similar way which means, similar kind of answers filled in on the answer sheet and that is certainly not what Design Schools are looking for.
All the best!