I have online shops. It grew well and eventually DH stopped work as well and it’s our family income. A few tips:-
Don’t give up the day job yet. It is still possible to build a business, but definitely much harder than it was.
Online marketplaces (eBay, Amazon, Etsy etc.) cost, but they will get you eyeballs cheaper than your own website. The best marketplace will depend on your product, but I find Etsy to be an awful lot of effort for little reward and dumped them last year.
Consider your hourly rate. If you are making less than supermarket wages with a lot more headache and little upward prospect then please give yourself a break and go and stack shelves. A hobby is nice, but you will drain the enjoyment out of it for slave labour wages.
Edibles and toiletries are a pain. Food safety certs, skin testing, allergies, best before dates.
Think about scalability now because if you take off you will have little capacity to be sorting things out when you are manically making, packing and shipping 24 hours a day.
Pricing - there is a magical price zone. Too cheap and you attract bargain hunters who want the moon on a stick for tuppence. These people are often demanding and hard work. They complain about stuff and basically want your product for free. Too expensive and people are reluctant to commit without either laborious hand holding or in person shopping. I want shoppers rich enough to be low maintenance and who don’t overthink about spending £40-100. Quality product, quality service. Don’t be the cheapest.