You can absolutely use websites like eBay and Etsy! Try listing some items and making a professional Facebook page for yourself with a link to your eBay/Etsy pages. Then share the information with friends and family and get them to spread the word to people they know. Also, make sure that you have detailed descriptions and multiple pictures with anything you list online. This will help your listing show up in keyword searches, and you are more likely to sell something if the buyer knows a lot about what they are looking at.
If you’re a skilled worker in a specific niche, like marketing, design, or software development, there are specialty marketplaces that cater just to you. These are amazing places to make money online as you know that the people visiting them are looking specifically for the skills you have. Check out places like 99Designs or Dribbble for designers, Cloudpeeps for marketing and SEO professionals, and TopTal, Crew, or Gigster for high-level software developers. Once you've built up your development skills, you can begin building a brand for yourself as a higher-value consultant and start charging brands for larger projects like implementing an entire WordPress security overhaul or migrating a website from http to https.
Now, making money online should seem like a pleasurable activity. Why wouldn't we do just about anything to see things through, since it would be a major source of pleasure, right? Wrong. In the beginning, like anything else, we might get really excited about it. We might also set our hopes very high. But that all comes crashing down when we begin to fail.