I'm very interested in this thread. I can't wait to to try Timothy's advice because something tells me that's the fast track to trills. I don't even have a piece requiring trills, but that isn't going to stop me from a little advance practicing.
Jmao, now when you look at all those other folks who play trills beautifully, do you see the rotation of the forearm and hand, plus the work of the fingers, perhaps. It's probably very slight since apparently didn't pick up on it to begin with. But now that you know what to look for...
We have a storm brewing so I disconnected my piano. But later, I expect to be in trill city. Thank you Timothy, Faulty Damper, Moi. And you, too NightinGale. I'll do that forum search as you suggested.