The correct ways to store your fabric is NOT the way most do it.
It should be folded or hund out of direct sunlight.
Moisture should be kept at a minimum as well.
Cotton is considered a living/breathing fiber. Meaning that even after being dyed/printed, it is still able to breathe in anything it comes in contact with. Cigarette smoke being the #1 thing we can all atest to ruining fabric.
But storing it in a sealed baggie, or tote can do just as much harm. It dries it out causing dry rot! Storing it in a closet or chest with bare wood, causes the yellowing as the acids in the wood make gas fumes that leach into the fabric. Storing in or on cardboard that is not acid free/archival board will cause bleaching out of the dyes as the acid in the cardboard makes fumes. All of these also cause detoriation in the fabrics over time.
SO if you are going to store it on a shelf, make sure it is completely painted/sealed. I also put down some cheap poly/cotton muslin as a shelf liner!
If using cardboard, make sure it is acid free(the bolts it comes on is NOT acid free and are meant for short term storage only).
The folding over the ruler to make each piece measure the same is the best way to make sure you know what you have and how much. It also makes for easy rotation!