5. Make purchasing fast. Have you noticed that nobody pays with checks anymore? Why bother filling all that paperwork out when you can just slide a card through a reader? The same rule applies online. Any time you force customers to take extra time paying, you run the risk of losing them. Integrating your site's shopping cart with all credit card processors (e.g., Authorize.net, VeriSign, PayPal) keep transactions fast and simple. Many customers also hate entering credit card and personal information, so help keep things moving along by keeping that information in their accounts after they've entered it once. Also, consider accepting options like Google Checkout and PayPal. Finally, make gift card and coupon redemption easy and allow international checkout.