First, it's important that you research your item before listing it. Collector's love when unknowing sellers list their items without researching it because they can snatch up the item at a bargain price and then sell it again with a higher price and a better description. Use your books on antiques and collectibles, check out websites, and consult with other collectors before listing your item. Second, always think twice before ending an auction early. If your item isn't bringing in the bids you were hoping for, don't panic. Many people wait until the last minute to bid, a practice called "sniping". Your bid price could double, or even triple in the last few seconds of your auction. Some people also send in bids via e-mail asking you to end the auction early. Not only is this against eBay's rules to avoid paying ending fees, you could also be cheating yourself out of a higher price that may come at the end of the auction. Third, when you are titling your item, choose words that pertain to the specifics of the item, such as the size, marker, color, or age. Avoid extraneous words like "wow", "must see", "huge", or "look". Since most searches are done on titles rather than on descriptions, this will allow more people to see your item. Fourth, keep your shipping and handling charges reasonable. Some people will avoid auctions with high shipping and handling charges altogether. Consider charging just what it will cost to mail the item, and then build your cost for labor and packaging into the base price of your item. Some people will also avoid auctions where the shipping and handling charges are not expressly stated. Be sure that you list the charges for shipping up front. It is not fair to charge high shipping costs after the item has already been purchased, and it will hurt your loyalty as a seller. Last, but not least, keep in touch with your best bidders. If you specialize in a certain item, such as glassware, it may be a good idea to set up some sort of email list to keep in touch with past bidders. Once you've got a list of people to contact, send updates weekly, bi-weekly, or monthly, and be sure to include links to the items you have for sale.
References
http://antiques.about.com/od/sellingantiques/a/aa110204.htm
http://antiques.about.com/library/weekly/aa060702.htm
http://www.powerhomebiz.com/vol35/antique.htm