What is the best direction to place an aquarium? I've read North, East or SouthEast wall. Out of these directions, I think North makes sense as it's water. Is this correct or is there a better direction?

Also, how important are these for the aquarium:

Size/Dimensions? I read there is a preferred size/dimensions for a work desk so how about an aquarium?
Any particular shape?
Type of Goldfish or any type of GoldFish will do? So many variations of Goldfish.
Lighting?
Type and color of gravel?
Preferred ornaments and plants in the aquarium?
Preferred background picture?

Anything else I should know before I go out and buy an aquarium with 8 goldfish and 1 black?

My KUA # is 7 and my partner is 1 if that helps. Thanks.

Marc