Training is not running the board or the automation system. It's style, knowing what to say, pacing, flow with the music, sounding warm, relating, knowing how to deal with tight segues, all that kind of stuff.
I seldom taught novices. Most people were already in radio and moving to a bigger station or bigger market. Fresno to LA, Arecibo to San Juan, Ibarra to Quito, Mendoza to Buenos Aires or Santo Domingo to New York. Much of the training was adapting to the format, getting rid of bad habits and understanding how to be a part of stationality.
My technique in most cases was to spend an hour or more going over the skimmer, and finding a good moment and one that was not strong. The good moment was played for the talent to insure that they know why I liked it and how they could continue doing that sort of thing. The weak moment was mostly, "if that happened again, how could you do it better?" and then discussing with the announcer how they could get even better.
I still have people I trained 40 to 50 years ago mentioning that to me on Facebook. It's very rewarding.
The toughest challenge is working with someone who is successful and getting them to understand that they can still grow. Otherwise, they fall into tiring routines and slump in the numbers. Since I was pretty terrible on the air myself, I can tell people "I know bad from experience. And if I know bad, I know what good is too."