One of the easiest and cheapest things you can do to build eCustomer goodwill and return business is "Proactive Communication." Many sellers use the shortcut of eBay's impersonal invoice. Bad thing! This is a communication from eBay -- not from YOU the seller. When buyers bid high, then lay their money on your counter, they always appreciate your personal acknowledgment of their purchase and your thanks. Simply put - along with the eBay invoice - initiate personal communication with your buyers the moment they win the bidding. Use your own email logo and letterhead. For initial contact, here is a useful template you can use over & over (feel free to adapt!):
(subject line) initial: Mixed Widget Lot - eBay #12345678900
Congratulations! Yours was the winning bid ($40.97) on the Mixed Widget Lot - eBay #12345678900 - auction ended 15 March 1885.
Our preferred payment method is PayPal® (ID: email@example.com). We also accept commercial or postal financial services, or checks drawn on U.S. banks (payable to Horace Thumprussle Enterprises, LLP). We ship the same or next day after your payment is confirmed.
Your best shipping options for this lot are Bazooka® Sidedoor Delivery ($14.16, includes insurance & tracking), or USPS Parcel Post ($14.69, includes insurance & delivery confirmation).
Thank you for your winning bid and best regards, HORACE
Second Bad Thing: far too many sellers fail to share tracking or delivery confirmation with their buyers. When you do, it gives them yet another layer of security -- to track their shipments moving from origin, through the transportation system, to their destination. I use this one:
Thank you for your recent payment. Your Lot-of-33 Rare Bolixx Buzzers - eBay 7070707070 - goes out Friday, 13 February 2107, to the above address via USPS Priority. Your delivery confirmation number is 75884269691021501 and the USPS delivery confirmation site is (hyperlinked) HERE.
...OR... via Whizzer® Couriers. Your tracking number is 000200128331701 and the Whizzer tracking site is (hyperlinked) HERE.
If this transaction meets or exceeds your expectations, I hope we can exchange positive eBay feedback. If not, please contact me directly so I can Make It Right. Many thanks again for your winning bid and your business!