E-commerce takes the inconvenience out of a customer having to deal in person with somebody when buying a product or service

From a customer perspective it becomes very attractive to buy what you want, when you want.  From a seller point of view, the obvious benefit is that your webshop can bring in business whilst you're busy doing other things.  However, in order to be successful, it has to do a good job of selling.

But a lot of people build an e-commerce website, expect the orders to come flooding in and are disappointed when it doesn't quite meet their expectations.

The reality of a good e-commerce site is that it needs to be optimised and tweaked to suit both the needs of the audience as well as the needs of the business.

The most obvious thing to check is price - do a quick Google for the product and see if anyone is selling the same or similar item for less.  So many websites are scuppered by cheap competition.  If so, then you'll need to heavily promote other features and benefits to win the sale

Delivery fees are another common roadblock.  Sites like Amazon have set the standard by delivering things for free, so that can be a customer expectation that's not met.

Unlike the Field of Dreams, building it alone will not make them come!
You'll need a good marketing strategy to get your website promoted to your target audience - take a look at the More Traffic section for free ideas on how to improve that

All of these things can influence the success or failure of an e-commerce website:

If your business has a unique selling point, be sure to mention that USP on the product page.  Many customers will arrive directly there and not even see the rest of your site.

Your USP may be as simple as you having stock availability when nobody else does!

Use good analytics to measure how customers use your site, so you can learn how to improve your Conversion Rate Optimisation (CRO)