Not going to answer how you ask.
You need to be quick and make garments that look good and feel comfortable and are not a problem.
At one time, for a long time, tailors made all kinds clothes for the male population (and some even made for females).
Specialist made certain kinds when it brought in enough money. Some Specialist, for example, only made white tie coats. They were good and lived in the right location. If they didnt want to live in one of those locations, then they made other clothes as needed. One thing for sure, don't expect to make a lot of money. When customers lost interest in custom clothing many tailors found other kinds of work. It's a fickle business. I hear some Savil Row tailors are now making jeans. Throughout the centuries now and then clothing expectations have made sudden changes and many continuous small changes. Nobody knows what the future will be. Used to be tailors were always at the top of this game. But, not so sure anymore. They should be. But, have the futuristic lessons been forgotten?
If you are barking up the wrong money tree, you will be disappointed. Many tailors sent their children to college, because the earnings are way higher.
Being aware of change and, capable of quickly doing it.
At one time tailors made ski clothing. Today ski clothing cloth is very different. Are there any real tailors that make ski clothing, anymore? (Synthetic cloth is different cutting methods, hot knife, vacuum to suck the deadly fumes out). Horse riding, only a few, nowadays. How many other kinds of clothes you can find to make a profit? Maybe you might do fine making only suits, sports coats, blazers, vest, trousers. Some tailors found they had to make themselves available, instead of, just exclusivety.
There are some who rolled in big money from working in the stock market, banking, etc.who gave it all up and found more satisfaction working in a trade, or some other lower paying job. Money doesn't buy everything.