Choose a main neutral color for your walls if you can paint them. Then 1 or 2 accent colors to use in curtains, toppers,
frames, etc. Color will bring the mish-mash together.
I painted my walls pale yellow. My furniture is white except for one brown dresser (yet to sell). Accents are turquoise and black. Since a sewing room, by its very nature, seems to look cluttered with all the "little" things, keeping the decor coordinated is easier on the eyes.