When I was unemployed, I made and sold stuffed animals online to pay the bills. Especially with feeling depressed with the job search, it was really nice to spend time around colorful thread and fabrics, and make something soft and huggable when I was done. The people I sold to were really awesome, I feel like I developed a relatively rare skill, and it allowed us to pay the bills without working fast food. Now I can make custom plush for friends or family that are unique, without worrying about the money. There were a number of tough parts, for me at least:
1. The advertising portion of gaining online sales/commissions was really hard. Photography quality is a huge part of sale-ability, and yes, I did see people with lower quality products drum up more interest because they took better pictures or did better advertising. Especially the scammy "like my FB page/1 giveaway for every 1k likes!" messages. They were effective, but didn't line up with my morals.
2. There's a big rush to find the next big fad/keeping up with the Jones's. Everyone wants to gain that bigger sales slice of the pie, and it really lead to this frantic rush. Minky! Embroidery! Socks! Airbrushing! And if you didn't spend into the latest "fad" it seemed like you lost a lot of potential $$. Or just struggled with feeling marginalized, depressed, or less creative.
Taxes were actually really easy. I kept a spreadsheet with every sale, how much I paid in fees, and every cent I paid for supplies. Come tax time, any tax software has an option for "business", walks you through the prompts, and you plug in your numbers. I think I paid ~$120 that year. There's some specific rules about hobby businesses and higher income businesses with quarterly estimated tax, but I never earned enough to be anywhere near those specialties. A few Google searches will probably find some helpful articles.