One suggestion I haven't seen is making sure that the height of your sewing table is correct. Go and sit at sewing tables in stores, and keep in mind the height of your machine. We redid my sewing room last year and adjusted my counter down about 3 inches. It makes a world of difference in shoulder pain.
Also, try to plan some small drawers into your plan. There are so many little things that can be kept in order with drawers, like note pads, calculator, ruler, extra bobbins, safety pins...etc. Have fun planning and creating your dream room.