Looking at an Etsy shop today I clicked on the listing for a necklace. I thought "Nice colours, and it looks like the sort of design and nice long length that such-and-such friend would like."
This seller is doing a lot right, and has respectable sales and feedback to prove it. But as a potential customer those nuts-and-bolts details are every bit as important to me as knowing her inspiration for the design.
The 20 Questions Your Buyers Are Asking article in Etsy's blog includes a handy checklist of things to think about when listing. After all, size isn't the only thing that matters!