everyone has to store their quilts in the space they have available...but having said that, is the question how to show as many as possible? then the suggestions here will help...if the question is how to protect those items not 'out' right now.... then take a tip from our grandmothers...mine, like a lot of people's, had a guest room with a bed that was layered with all her quilts. One of our treats during a visit was to see her own private bed-turning as she pulled a corner back and explained when and where and who this one was made for or with.... storing them flat is THE best thing for the quilt itself....second? get cardboard rolls from a florist supply or yardage store, wrap in an old, clean sheet, do NOT let your quilts touch cardboard, it will discolor them. Then roll the quilt onto the roll...you can put 2 or 3 on the same 'core'.... then wrap on the outside with another clean sheet to protect from dust. If you MUST fold a quilt, which I would just Never do, other than for travel, then fold in thirds both directions...how many quilts have you seen with a little 'pup tent' in the center of the quilt from being folded the same way for years! When talking to quilt groups, what I say is, "We never fold our quilts in half, because everyone else always will." Just doing it differently will help.... and then, set a schedule for yourself... twice a year, try when the clocks change, get them out of their boxes, air, fold in a different way and then replace.... NO PLASTIC unless it's going in the mail....NEVER....
Put them on a bed if you have an extra...they will look new for decades...