You can tap into a person's motivation by having the trainee access the value they'll receive. In many cases, their highest value for learning a soft skill will be improving their family or social life. Information Understanding poor information creates poor results. Understanding quality information creates quality results. Also, the simpler the better.
Powerful information delivered in a simple, concise format can provide powerful results.
They need to use the skill over and over again. The objective is to cause the trainee to feel the skill is a familiar part of their behavior. Too many times, an excellent skill seems unfamiliar. But once they have used the skill a few times, it becomes more natural and the are more inclined to use it. When they use it often enough, it becomes a part of who they are.