An easy entry is with the online market, such as eBay. This has real benefits. It's wise to gain some experience selling online prior to launching your own business site. Better to make mistakes on eBay than to damage the reputation of your own site (which will cost more money and time to build). A few sales on eBay will quickly reveal what online buyers expect and how they are different from your existing offline customers. For example:
How detailed your online customers expect items to be described/graded
How fast they expect to be contacted after a purchase
How they prefer to pay for their items
How fast they expect their merchandise to arrive
How your product pages, sales policies, and promotions are received
How to ...