
Having a good looking and a secured (with https:// instead of http:// in the beginning of URL) website also counts when selling online. Keep your customer secured and happy to buy products and services from you.
Whatever comes with that like good marketing and people talking about your eCommerce website can only help you. What you do about and with your products and your services is also another story. Things like pirating tools or other things sold on your eCommerce website can bring you down a little. It won't be a complete bring down in the case of Amazon but too many things like this will clarly do that. They are already counting in case of Amazon even if you haven't seen it yet.