I usually do a search on the stamp set for closed auctions to see what they sold for recently. Some sets are more sought after than others. If there are a lot of them that didn't sell or sold really cheap, I don't bother listing it.
When I wasn't a demo, I found that offering shipping to other countries helped items sell.
Lorien <--My Blog
Giggle Mingler (Hee hee)
"A raω onion ωould pгοbably be rubbеd on unbroken сhildbrainѕ with гeрutablе gaіns." - Comment from a Blog Spammer as Read by me