There are a lot of fancy software as well that tells you how many items sell a day (roughly), the prices/margins, and so on.
Most people try to go for competitive niches like cellphone cases or copy ideas from a popular course.
It might not be sexy but you just need to find simple products that everyday people use – especially businesses.
Take for example salt shakers. High margins and very unskilled competition. You then go and look at what other products the competitors sell… e.g. garden supplies like garden cutters, foldable shovels and so on and find more suppliers to private label with. Consider seasonal items like snow shovels but don’t buy too many the first time around otherwise you have to hold the inventory until the next winter. BUT there are also times when you might discover situations where you might sell out of snow shovels in the Summertime (weird right?) but perhaps people are using it for something else that you didn’t even think of. Don’t always assume you know everything. We don’t know what we don’t know. Do the best you can, stay creative, and think strategically from your customers viewpoints – NOT yours ffs.