When thinking about an online storefront, remember that your shop “usability” will greatly affect your sales. In this case, usability means the ease with which customers can perform the necessary actions at your site -- for example, searching for a product, filling out an order form, checking shipping costs, etc. No doubt that if other conditions are equal, the site with better usability will sell more products. If a site is hard to navigate or the check-out process is not thought out clearly or it just looks awful, customers may leave without buying and certainly won’t bookmark this site for a possible future purchases.

So, what are the most effective ways to make an e-commerce site usable? Usability is the subject of an entire field of study which involves users groups testing, even including the fixation of human eye movements to analyze which Web page elements are noticed first.
For an introduction, the following list presents some elements of storefront design that most usability experts consider to be essential.

	Make the beginning of the checkout process and continue shopping available at any time of your site visit.
	Make registration to your site optional as it may become a serious barrier for first-time and one-time customers. Instead you can make the registration an optional feature and provide strong incentives to register.
	Allow users to make changes in quantities of items in their shopping cart, remove and add items whenever they want.
	Provide a visual confirmation of adding items to their shopping cart to ensure your customers that the actions they take work.
	Provide information that your customers may find useful before purchasing. Give links to pages containing information about  return policy, guarantees, shipping and delivery information, product details.
	Give clear explanations to illustrate each step of the checkout process.
	Guide shoppers by highlighting buttons that lead to the next step of their buying process.
	Do not make your customers retype all the information in case they want to change an entry details and wish to return to the previously viewed pages. Advanced (usually custom) e-commerce solutions may allow you to preserve information entered by a user and even give users opportunities to interrupt their order process and come back later to continue.
	Provide a summary of the order summary before a purchase is completed. Display everything that the customer has entered and ask the confirmation of all order details.
	Let your customers be aware of all shipping charges details as early as possible. Do not ask to provide full personal information before your customer is strongly committed to make a purchase. Instead request only minimal information necessary to evaluate shipping and taxes, e.g. zip code or Province/State name.
	Provide clear explanations if any entry errors in order forms occur. Display a message indicating that a problem exists, name the fields that have to be reentered or corrected and any other information how to fix the error.