If doing a brick and mortar shop -
location? parking? access? demographics of area? (can people afford to buy quilting supplies?) competition? Hobby Lobby, JoAnn, and/or other quilt shops?
Would your location be near something a lot of people would probably stop at - such as a chain/large grocery store - or would it be a "destination" - such as in a house in the middle of a pasture 20 miles from the nearest town. (There is a shop in Florida that seemed to have those characteristics.)