For me... when the rocket doesn't have vertical text (like the Saturn V)
U
S
A
I prefer to have my flamey side on the left, and the pointy side on the right (when the rocket is horizontal). The only exception to this is when I fall in love with a design that is orientated the other way on the facecard/instructions. I do tend to get annoyed when the decals are orientated in such a way that you have one side upside down when the other side is oriented up.