Think first of compelling content that is useful rather than product promotion. If you're not one of these, then make sure potential customers can find you from them. Also use proven techniques to ensure that you come high up on search engine results. The style must reinforce your positioning and branding. Too many sites are overloaded with irrelevant graphics at the expense of quality information.
Buyers can progress, gaining familiarity and confidence as they go.
Use payment service providers to process credit card transactions within seconds. Spell out prices in US dollars and Euros. Conduct random tests as a customer. In particular, as my opening examples indicated, you must measure how well your various functions perform in terms of responding to queries and achieving fulfillment. If you think through carefully the new opportunities that the internet creates, then you should completely rethink all your organisational processes.