Found another good post I thought I'd add to the mix
13 Tips For A Better E-Commerce Website
Software
1. Use A Well-Tested Software
2. Have Scenarios In Case An Unexpected Thing Occurs
Presentation
3. Adding To Cart Without Registering
4. Reaching To The Product With Less Clicks
5. There Is Never "Too Detailed Products"
6. More And High-Quality Photos
7. Show Related, Alternative And Complimentary Products Better
8. Use SSL In Every Page When Collecting Critical Data
Order Processing
9. Notify Users On Every Level
10. If Something Goes Wrong, Contact With Phone Besides E-mail
Support
11. Detailed Knowledgebase
12. Provide Live Chat Support
13. Do Your Best To Prevent Support Calls But Have A Phone Number