You are selling in a very competitive market. There are so many similar listings on eBay (not to mention other online platforms). Then there are B&M shops selling similar fabric etc.

Many of your competitors have 100s or 1000s of items listed. Given how many you have available you can't expect to sell much more than you're currently selling.

I'd aim to dramatically increase your amount of listings if you want to increase your sales. I realise this is not possible for everyone due to time constraints etc.

Good luck