Designing a good e-commerce payment flow that also converts well is hard. What's the best flow you've seen? Do you have any resources with guidelines to design such flows?
Baymard wrote an extensive report on this (http://baymard.com/checkout-usability). If you can afford the $150 price tag, I think it's a good resource to have.
Smashing Magazine also has an article that covers some guidelines: http://www.smashingmagazine.com/2012/09/04/the-state-of-e-commerce-checkout-design-2012.
Thanks Nicole! :D