I’d say know your market first. If you like the idea, doesn’t mean that it is going to be a success. Do some research: find out what do people search for in your niche and area by using keyword tool planner – https://ads.google.com/home/tools/keyword-planner/. Here are some great tips if you decide to start selling online https://www.youtube.com/watch?v=2wfqyRLyMvU, https://www.oberlo.com/blog/online-business-ideas