What necessary things can we practice to ace situation test of NIFT?

Well for the written exam, practice maths and logical reasoning and try completing model test papers available online on time. For drawing, the more you practice different types of question the better it will be. And for situation test, practice using a variety of materials that are provided in situ

You can practice making paper models. How to use wires, straw, pins, etc. You can also watch YouTube videos for some videos.