Understand how a niche website works. A niche website focuses on very targeted, specific information. The content must be specific, useful and interesting to your target audience. Successful niche websites get anywhere from 1,000 to 10,000 visitors per month. You build content on a particular keyword, and you make passive income with Google Adsense or through affiliate links.
If you're ready to enter the ecommerce fray, you could sell your own stuff. Of course, along with selling your own stuff on your own website comes a whole slew of both responsibilities and technical configuration and requirements. For starters, you'll need a website and a hosting account. You'll also need a merchant account like ones offered by Stripe or PayPal. Then you'll need to design that site, build a sales funnel, create a lead magnet and do some email marketing.
Selling clothes you no longer wear is a quick way to make some money. Start with local consignment shops for faster cash, or use sites like ThredUp and Poshmark to find buyers. If you go the online route, be sure to take clear, well-lit photos of your pieces and research similar items to set competitive prices. Get tips on how to sell your clothing.