The 70/30 ratio in concept design.

This is a great collection of sci-fi design tips from "Cubebrush" on youtube:

Something he covers and something I have seen pop up in conversation over the years is the 70/30 ratio.  Basically 70 percent of your subject is reserved for letting the eye rest or wander over the form where the remaining 30 percent is used to punctuate the form.   

You can see here how the principle is applied.