Below is a link to a long but very interesting article on how to teach more effectively. I think we already know that good teachers or trainers are what makes the difference but a quote in the article makes it very clear:
“Professor John Hattie, of the University of Melbourne, has undertaken a rigorous assessment of the thousands of empirical studies that have been carried out on educational achievement. He concluded that, other than the raw cognitive ability of the child herself, only one variable really counts: “What teachers do, know and care about.”
The article references a book title ‘Teach like a Champion’ which you can access at Amazon if you are interested.