There's an audience for everything, even if it's as specific as dollhouse furniture or organic dog food. With a niche e-commerce store, you can reach customers who seek your specific products. Building a business in a niche market can help you differentiate yourself from other brands and build your credibility and expertise. Look to social media or your own consumer needs to come up with a product to sell online.
The internet changes so fast that one year online equals about five years in the real world. But the principles of how to start and grow a successful online business haven't changed at all. If you're just starting a small business online, stick to this sequence. If you've been online awhile, do a quick review and see if there's a step you're neglecting, or never got around to doing in the first place. You can't go wrong with the basics.