Many people follow the mantra of "If you build it, they will come" for online business. It may be true if you have an offline business in a good location, but online you need traffic. If you don't know how to market, setting up an online store won't make you rich. But if you have a good product, know how to get the word out about it, and you're looking to utilize the Internet to expand your customer base, then setting up an online shop makes sense.
Find the right store package. The days of getting a “shopping cart” from here, “payment processing from there” are pretty much over. The trick for setting up an online shop now isn't being tech savvy, it's figuring out the company with the right package for your needs.
Build a separate website to serve as a hub for your business and attach a link to your store. If you can provide a website with good quality information about the type of products you sell, you add a personal touch and build trust in your potential customers before they buy from you.This is especially important if you're selling information.
Take photos of your products and upload them to your store. With the exception of ebooks, which will have an image you most likely will have created with a graphic design program like GIMP or PhotoShop, most products will require a photo to entice customers to buy. Make sure you use a high-quality digital camera to make taking and uploading pictures easier.
Market your store to drive traffic to it. Treat your online shop just like you would a brick-and-mortar business. Advertise both in the online and the offline world to drive traffic to your website.
Some companies/shops to consider for your store package: eBay (for reselling), Amazon Marketplace (for books), e-junkie.com (for hard goods or digital goods), etsy.com (for handmade goods), Yahoo Merchant Solutions (just about any type of store), and don't forget Cafepress.com and Zazzle.com (for your designs on general products like T-shirts and mugs).
Buy your own domain name for your website. When you do print advertising or any other advertising, someone is more likely to go to a website set up as storename.com than they are to go to a long web address that starts with Cafepress or ebay. That small investment in a proper domain name and hosting will make the difference between looking like a business professional and looking like someone without a clue.