All of the above answers!
Seriously though, provide an appropriate place to scratch. Some cats prefer upright scratching places, others like those on the floor. Offer both and a couple different types.
Try to keep the blanket from her if you can. You may want to consider using one with a different texture if you can.
Water bottles can work, but unless you can catch her every single time she does it (meaning she's never left alone with the blanket and you are awake the entire time she has access) it probably won't be an effective means of "punishment."
Soft Paws (caps that can be put on the nails) are an option, but they do fall off and need to be replaced either then or when the nails get too long so there can be considerable upkeep.
PetSmart carries some products that can be sprayed on surfaces to make them less attractive to cats, but I'm not sure how/if they work on fabrics. It at least is worth checking out.
at 11:52 PM on Aug. 8, 2010