Developing a business over the Internet requires many of the same major activities as starting any other business. You should do some basic business planning. After all, you need a product. You may need funding to get your business going. You need customers. You need to market products to your customers. You need strong customer service. You need to manage purchases by customers, finances, staff and other resources.
Probably. Much depends on the nature of your business. Web site such as Amazon.com and Barnes & Noble have established their hold over the book market, and their sheer size, name recognition and the relationship of trust they have with their customers allows them to dominate this market with good pricing (due to economies of scale) and remarkable customer loyalty.
Business "intuition," popular in the days of pen, ink and paper, was the first "BI" -- keen and quick insight rooted in trading experience and utilizing heightened observation with direct perception of commercial reality, all aided by strong inferences and at least some minimal amount of basic information.
A Web site doesn't need to exist solely to sell your product online. It could supplement the sales of your already established retail store. If you sell a unique product, such as wheat grass or gourmet chocolates, you might find success reaching others around the country (or the world, for that matter) who do not have access to these products in their own towns.
Basically, you need an "online store" to be an "e-tailer". (Don't fret. You may be able to outsource, or hire, a current store to work with you.) Your store will need a "merchant" account, or the ability to process your customers' credit card transactions over the Internet. This includes needing a "secure server", or that your online store be on a computer system that ensures that customers' credit card numbers cannot readily be read by people who are not supposed to read these numbers. You'll probably need some kind of online order form that customers can complete, in order to purchase your products. You may even want your the processing of customers' order to include processing the customers' credit card numbers right away while they're still online and connected to your Website.
You'll need a computer system to manage information for your business. The size of the system depends on how much you want to do with it. However, today's desktop personal computers (especially if they're configured as part of a client-server system) can handle many of the demands of e-commerce. (Note that you may need a different computer system to actually host your Website, conduct financial transactions with customers, etc.)