Just be sure to put a lot of care into your product listings. Everything from the titles you use, to how effective the description is at convincing potential buyers your product is better than the rest, and even taking care to shoot high quality product photos can have a dramatic impact on your sales. I recommend using photo editing tools like Fotor, which gives you the ability to edit your images, create captivating graphic designs and more.
People are always looking to have their cars washed and detailed. You could be a mobile car washer and detailer without having a permanent location. Reach out to people you know or make some flyers and put it in your neighbors' mailboxes. If you want to get serious about it, prop up a one-page website or give out business cards. You can make money quickly doing this.