I have wanted to organize my tablecloths for a long time.
I buy tablecloths at thrift stores, estate sales and garage sales. I love vintage linens, they are usually high quality cotton and feel wonderful to the touch. Newer tablecloths have polyester added to help keep them wrinkle free but nothing feels like good cotton!
I looked for an iron-on label like the ones they used to use in dry cleaners to label peoples clothes. I'm sure you can get them, I couldn't seem find them in my local fabric store.
Then I found these labels from Martha Stewart Home Office at Staples. These are No Iron. Don't iron them! They melt onto your iron. I thought they said Iron-On instead of No Iron.
You use a sharpie to write the length and width on them, it dries super fast then you stick it to the back of the cloth. They are thin and flexible and you will not see them from the outside of the tablecloth. They are washer and dryer safe, just make sure to iron the opposite side of the cloth. :)
In fact if you buy anything from the Martha Stewart Avery Line at Staples before 12/31/12, use this coupon for 40% off.
It is great to have a chart to reference so I found this one, printed it and taped it into the closet where I keep my tablecloths.