This is a pointer to one of my favorite darts technique articles.
While there’s something terribly German about his attention to detail (not always a bad thing) he covers the 3 main physical aspects of the game.
The only thing I disagree with is that I don’t believe there is only one correct stance. His other stance comments are all good but I think you can throw well with anything from a “both toes on the line” stance to a full-sideways one.
Of course I have to say that since I’m not far short of a full face forward stance myself. But it’s still true. I do agree that if I was taking an absolute beginner to his first trip to the oche I’d have him stand pretty much like the author says, but I wouldn’t waste any time “correcting” the stance of someone who’s thrown for a few years in any position.