7: Make Them Wait
The WWW stands for World Wide Webnot World Wide Wait. Shopping sites are a challenge to design. You want to keep page-download times low while at the same time allowing customers to see what they're getting. Don't use bells and whistles just because you can. People don't want to have to download anything to view your site. If you must use plug-ins, tell your customers where to get them. Be sure to include links to the software necessary for a full appreciation of your site. If you say your site uses RealAudio, make sure it links to a download page for RealAudio.
As bandwidth increases, this issue will become less relevant. Until then, heavy use of graphics, video, and audio programs is time-consuming for the user.
Next, keep in mind that people want simplicity over cool graphics. Faster loading is better than eye candy. So keep your graphics small. Small is better where images are concerned. Try to keep them less than 10KB each, and your download time will speed up. If heavy graphics are necessary to display your offerings, at least be sensitive to customers with older systems. Offer a text-only option for viewing your site.
Finally, remember the three-click rule. It should take no more than three clicks to access the information they need. That means three clicks to a Buy button.