I have an extra room in my house that we use as a computer room, classroom, sewing, and craft room. Since none of those activities need a closet, my husband converted the closet in the room into a storage space for my sewing supplies. I don't think I could ever have too many shelves in my house, and these particular shelves are extremely handy.
I keep a stack of fabric on them:
Sewing supplies are organized and kept in a variety of storage boxes:
Embroidery floss is organized by color number in plastic boxes. This particular box was originally intended for fishing supplies:
And I even have some floss that I dyed myself:
I also keep my sewing thread in a plastic box, books on the shelves, a variety of cute ribbon, and jars filled with buttons. I honestly don't think I could ever have too many jars of buttons. I'm not sure why, but they just fascinate me.