Do your research before listing. Knowledgable bidders love it when sellers are too lazy to research their items before putting them up for sale on eBay. Those sellers consistently offer them bargain after bargain, which can be sold again on eBay with a better title and description for lots more money. Use your books on antiques and collectibles, Web sites like this one and conversations with other sellers to learn about what you're selling on eBay long before you attempt to auction it off.
Think twice about ending an auction early. If your item is not bringing in the bids you expected during the course of the auction, don't panic. Since many bidders wait until the last minute to bid, a practice known as "sniping," the price on a desirable item can double or even triple during the last few seconds of an auction. If a potential buyer makes you an offer via e-mail to end the auction early and sell the item to them outright, that's not a good idea either. It's not only against eBay's rules to skirt around paying ending item fees, you could be cheating yourself out of a high ending price by selling to someone making a lowball offer.
Consider search keywords in titles. The small amount of space you're alloted for an eBay item title is valuable real estate from a selling perspective. Why? Most searches on eBay are done on item titles rather than descriptions. When you leave out specific keywords pertaining to the size, maker, color or age of a piece in your item title, fewer potential bidders will find your wares. Consider replacing extraneous words (such as wow, must see, huge and look) with pertinent detail words most bidders would use in a search. To do this, put yourself in the searcher's shoes. Do you think a bidder will key in "signed lovely old sparkling choker" as a keyword phrase? Perhaps "vintage clear rhinestone necklace by Lisner" would be the foundation for a better title.
Keep your shipping and handling charges reasonable. Shipping and handling charges can really jack up the cost you pass along to bidders. Some folks avoid auctions that quote very high shipping and handling fees altogether. Consider charging only what it costs you to mail the item, and build in the cost of packaging and labor into your starting price instead. And if you're not stating the shipping charge in your listings already, be sure to do so. Bidders want to know how much they're going to have to pay to get their buys home before they bid. Again, some people will avoid auctions that don't explicitly state shipping charges up front. It's not fair to spring a high shipping fee on a bidder after the fact, and you sure won't earn buyer loyalty that way.
Keep in touch with your best bidders. If you specialize in certain items such as glassware, pottery, toys or jewelry, consider setting up email lists to keep in touch with past bidders. You'll want to ask them before placing them on the list so your email won't be considered spam, of course. Once you've compiled lists of people interested in your specialties, you can keep in touch with them weekly, bi-weekly or monthly to let them know when you've listed items they might be interested in viewing. Include links directly to the items, or to your seller's list in your communication.
Pamela Y. Wiggins, About.com's Antiques Guide since 1999, is the author of Buying & Selling Antiques and Collectibles on eBay. Click here for more information on Pamela Wiggins.