Read course reviews for popular courses. Look at the mediocre and low star reviews, what is it about the course that people want more of, use those weaknesses to your advantage. If everyone is complaining about the lack of the same thing, you should focus on adding it to your course. Be sure to look at what people loved about the course to ensure you also include favorable features. When creating an online course, look at the list of topic covered in it to ensure you include all of those topics in yours as well.
Look, I know it’s not always realistic to pull these off; I personally wouldn’t bother trying. But if you’ve got a ton of stuff lying around — not outright junk, but stuff you don’t need, like the aforementioned DVDs and kid’s clothes — it’s worth a try. Advertise on Craigslist and put up signs in your neighborhood, then come Saturday haul a table out to your driveway (assuming you have a driveway), load it up with stuff for sale, and take whatever you can get.
Graphic design is an amazing skill that works with several money making ideas. You can go the print on demand route and sell your designs on your own custom products. Or you can pitch your designs on a crowdsource platform like 99 Designs. You can create your own graphics, templates and more and sell them on marketplaces like Graphic River or Creative Market. Or you can pick up some clients and work as a freelance graphic artist.