Negative space is the space behind the object. For example, if you put your hand on a whiteboard and you trace it, the negative space will be the space around the hand. I found my negative space for my cutout drawing by matching the background paper to the template and cutting out the template.
For my regular still life drawings, I found the negative space by drawing the shape of the objects and then shading around it. I also tried to shade around the objects instead of drawing it before it. That tactic didn't work so well.
Negative space helps an artist draw something because if you are doing a print, you need to know the negative space to make the print have what on the paper.
I think that seeing negative space, if done right can be quite beautiful and it would help your understanding when you are drawing something complicated.