Some time ago I found an excellent eBook about better conversions on web shops. The book is written by Rick Broadhead and prepared exclusively for PayPal merchants.
The book was free to download from PayPal, but unfortunately I did not find the download link anymore. So, I suppose there's nothing wrong to attach the book here for Ubercart community to enjoy (if site maintainers see this an issue, please feel free to delete)
[It looks like you can fill out the form here to get it. --Lyle]
However, this book is pure gold for developers and merchants. It also comes with a nice check list with detailed instructions to follow, in order to build a killer shop that converts like crazy!
Something for starters:
1. Use clear navigation buttons..
2. Build continuity into every phase of the checkout process.
3. Identify any limitations or restrictions at the beginning of checkout.
4. Minimize the number of pages during checkout.
5. Donâ€™t make customers do unnecessary work.
6. Donâ€™t display redundant information.
7. Display steps during checkout.
8. Keep the checkout flow consistent.
9. Avoid clutter.
10. Be specific when requesting information.
11. Justify your request for personal information.
12. Give customers the option to check out as guest.
13. Prepare customers for sticker shock.
14. Tell customers when youâ€™re not going to charge them.
15. Tell customers they can make changes later.
16. Allow customers to save their shopping carts.
17. Use clear, non technical language.
18. Use third-party security certification.
19. Display contact information and store policies throughout the checkout process.
20. Avoid â€œdead endsâ€.
21. Make sure customers can return to the checkout.
22. Provide multiple payment options.
23. Provide receipt.
24. Offer to help customers about to abandon their purchases.
25. Remind customers of abandoned purchases.
26. Test your online store again and again.
27. Invest in your loyal and repeat customers.
Hope this gives some ideas, Merry Christmas from Sunny Spain