The question calls for a long discussion, as the test itself comprises of things like observational awareness and creativity.
But in general, the factors to keep in mind are :

• Try and think of various ways to approach the theme/topic
• Always make a habit of observation
• Work with different type of materials to have a good variety.

For further reference, check out the link below.
https://design.careers360.com/articles/nift-situation-test