Hi havenindia,
While I am not an expert, I could think of the following areas where you can promote your shop subscription service:
YOu can add the link - "Add me to your Favourite Seller/ shop List" in all your listings.
mail the link to all your previous buyers or prospective buyers.
Add this link in your Shop listing header that will automatically appear in all your Current and Future Listings.
In your thank you / feedback mails to your buyers.
also, We had couple of workshops in the past, which might have some information that you can benefit from:
Optimise your eBay Shop
Get better results out of your eBay Shop
I hope this helps!
Regards,
Sapana
