I would just add it's a good idea to use rolled up acid-free tissue paper inside the folds of the quilt to minimize creasing at the folds. Or, you could make some lightly stuffed rolls out of old sheets to insert at the folds.
Just make sure the quilt is not in contact with any wood or paper products, including cardboard, unless the paper and cardboard are "archival quality". That means they are acid-free. Regular wood products -- including cedar chests, paper, cardboard -- all contain acid which can eventually destroy fiber.
Oh, I also remembering seeing a magazine article that recommended folding on the bias rather than on the square. Folding on the bias is supposed to reduce stress on the fibers. I Googled to see if I could find directions and found this:
http://appliqueandpatches.blogspot.c...t-folding.html