Have clear payment policies but offer your buyers as many payment options as possible. State clearly that you do not ship until checks clear. Require certified methods of payment for big-ticket items. Here's a review of the different payment methods available, traditional and online, with the ups and downs of each.
Upside: One of the most popular and easiest methods for buyers.
Downside: Checks delay shipping because the seller should wait for each check to clear before shipping.
Upside: Payment is secure because it is drawn on a bank or the U.S. Postal Service (USPS). Seller can ship upon receipt of payment, expediting fulfillment.
Downside: More burdensome, expensive for buyer, who has to purchase the ...