It would be nice to have some room to walk between the aisles of fabric. One shop I go to regularly is so crowded that it is easy to push bolts off just by walking by.
Have the patterns available to the samples you display.
When fabric is cut, please be a little generous. When the sales person cuts right on the yard line, it doesn't give me any room for shrinkage. On occasion, my cuts have been short by a bit on one side too.
I like music to be understated, smooth jazz or something like that.
A clean bathroom area with paper towels and soap.
Coffee is nice, but in a separate area.