To start an online business it is best to find a niche product that consumers have difficulty finding in malls or department stores. Also take shipping into consideration. Pets.com found out the hard way: dog food is expensive to ship FedEx! Then you need an ecommerce enabled website. This can either be a new site developed from scratch, or an existing site to which you can add ecommerce shopping cart capabilities.
The contemporary e-commerce trend recommends companies to shift the traditional business model where focus on "standardized products, homogeneous market and long product life cycle" to the new business model where focus on "varied and customized products". E-commerce requires the company to have the ability to satisfy multiple needs of different customers and provide them with wider range of products.
To make things easier, compare vendors using the spreadsheet you created earlier. Create a table listing all the things you need in your ecommerce platform, then put the vendors you’re considering in different columns. This will allow you to easily tick off the features that each vendor can deliver. If a platform doesn’t have a feature you need, write down if and how you can work around it (i.e. use a third party integration, develop a custom solution).