Communicate! Get those invoices out soon after the auction and make sure the message is a positive, informative and grateful greeting. If a seller has questions, answer them. If you don’t already use the US Postal Service’s “Click and Ship" (where you can copy in an email thanking customers for their purchase and let them know you have mailed their item) start now --it's easy efficient and FREE. If you don't use the integrated mailing system, do send customers a quick canned email through Ebay that you sent the item (and when), providing a tracking number if you have one. With USPS "Click and Ship" they can also track their own package. People love knowing when their item is likely to arrive. For you, as a seller, it is a couple of keystrokes to have a canned message and to copy and paste it and hit “send.” You will be amazed at how important this type of customer care can be. It can bring plenty of business your way through repeat customers and word of mouth because you are efficient and communicate.