During my many years of teaching, I have found that no single method works for all students, all subject matter, or all expectations of successful results.
An instructor first must understand the subject matter thoroughly (far beyond the level of the course content), present illustrative stories pertaining to key learning goals and care that each student understands the presented material.
I believe that students can see a clear path to their success through an instructor’s efforts to motivate them -- keeping the presentation as clear and simple as possible -- by repeating key elements throughout the course.
A training course can be presented to students by using hundreds of slides that contain thousands of pieces of information pertaining to the subject matter, but realistic expectations should be that students complete a course with a thorough understanding of about 20 key subject items -- the main points of the subject.
Learning, understanding and applying knowledge is the key to success.