Stand behind your product and service on eBay
Offer an unconditional money-back guarantee on every thing you sell. If you are selling cars or houses, or “as-is” used goods that may not be a good idea – but the simple offer of a satisfaction guarantee will dramatically increase your sales. Even unhappy people rarely go to the trouble of sending something back.
The cost of providing the few refunds will be far out weighted by the increased volume of your sales. At the very least offer a guarantee that your items are exactly as described and you will give a full refund if they are not. If you have a return policy (and you should) be sure and spell it out clearly at the end of your auction description or in the form eBay gives you to do this.