As most have pointed out, you must first investigate your niche to make sure you get traffic, but the most important thing is to make sure there is a market for your products.
What I did was to think of a niche that could have a potential and then investigate that niche in terms of long tail keywords, search queries, monthly search trends, etc. Then, I do a search of these search terms to see what the others are. The sites are and with whom I would be competing. If it seems good to me, I will do it based on the possible financial gain, not just because I have a passion for that niche.
To give you an example on the morning of October 22 (two weeks ago, this Thursday) I had an idea based on my son's behavior, so I did a little research on this particular niche to discover that there were 140000 searches in the Kingdom United. for some of the long-tail keywords, then I niché more to sell a particular group of products and I got a trend of 9900 searches with little competition in the UK, then I looked at the other sites and I think I can soon make the number 1 , but that still takes time, especially with a new domain and without authority.
The domain was purchased, which exactly matched my long tail keyword, I could not really believe it was still available, and I had FSB installed with products in an hour, it was up and running and ready to go.
I added some useful articles that provide value along with some videos and I will have a new design this week, which will be implemented during the weekend. My hypothesis is that if I can create a design that matches the niche where it is familiar to the mothers or fathers of the children, then it will be more successful, we will see.
The result is that I have more than 40 indexed URLs that go down almost every day and traffic is gaining momentum. I've already had 3x sales, although I have not yet sent, so you do not know what the amount will be, but it's better than nothing and, of course, it will only improve, especially at this time of year.
This niche is not really something that interests me, except for the opportunity, so you do not need to continue with your passion, but it helps. I do not write the articles myself, I outsource them.
So, it's best to do a little research, since you will not waste your time and effort and, of course, will keep you motivated if you get sales in a niche where you feel passion.
I hope this helps