Training sticks when it moves an employee through the four stages of competence: teach the skill, role-play it, then drill it in bite-sized lessons until they do it without thinking. Showing somebody once isn't training; it's exposure.
Ever had an employee nod through the training, then discovered they can't do any of it on the floor? You didn't train them. You exposed them. Exposure is showing someone a D major scale on the piano and expecting them to play Piano Man. They saw how it looked. They never practiced.
Picture the four stages as a hill they move up from the bottom, as unable to do the job, to the top and back down as a confident associate. For the full version of how the four stages play out on a sales floor, see How to effectively develop the best retail sales skills.
Stage one is unconsciously incompetent. They don't know what they don't know, doing whatever seems right to them. Every new hire starts here, and so does every veteran who was never trained.
Stage two is consciously incompetent. You've taught them, and now they know their old way was wrong, but they can't do the new way yet. This is where most retail training dies, because a seminar or a book gets someone exactly this far and no further. The owner checks the box, the associate feels worse than before, and the floor never changes.
Stage three is consciously competent. After teaching plus role play, they can do it if they think about it. This is where drilling and quick wins live. Practice on the floor before doors open, where mistakes are free.
Stage four is unconsciously competent. They do it without thinking, the way elite athletes and working musicians perform. That's the goal, and the only road there is repetition in bite-sized lessons.
The test of your program is simple: do your people role-play and rack up quick wins, or do they watch and nod? You can only hold employees accountable for what you actually trained, and exposure isn't training.