If you decide that you want to sell products or services to retail customers, try and find a niche that is under-served by your competitors right now. This is the key to starting an online retail business because you want to find an area where there is little competition so you can dominate. To find some of these under-served niches, search for: “hot niches”
Finally, if you decide that you want to do business-to-business selling, figure out how you can provide benefit to the particular market that you want to go after. Many people work online as freelance writers. You can do this and potentially differ yourself from the competition if you market to one particular niche. Business-to-business selling is similar to the retail strategy in that you want to focus upon a niche and try and dominate that niche.
Hopefully this article on creating and starting an online business gives you an idea on which of the three areas you would like to focus.