Location is also important. Like the real world, you want a good amount of traffic. However, you'll find that setting up a shop in a cluster of 20 shops would probably be a bad idea, as your shop will go less noticed. So setting up your shop say... outside of Ciar is pretty good business whereas setting one up near Alby... probably not a good idea.
You also have to assume what your customers can afford at that location, so like my example of Alby... you might find a high flow of newbies that don't have the free cash on hand. Still this doesn't mean that you should sham players at Ciar because they get 10-20k per run on Basic.
Also, for price guidelines, check out
TofuCakee's thread. It really goes by demand, so the prices are actually up to you to set. Like, Well-done Chicken Wing(+28 hp +10 Luk, +1 Lower) really don't sell for 1000 on Mari, I've been selling them for 700; you will still make a good margin of profit! However, undercutting the market is probably the worst... as everyone will have a hard time making money on low margins... so lets try not to do that!