Im no expert, but what I do know is that everyone learns in different ways, and many struggle with applying what they have learnt.
There is numerous information available online about the different learning styles, which may assist you.
Speaking from my own experience, even though I was equiped to do my job....I struggled with my desktop publishing skills. My trainer discovered a method which worked for a multi-tasked person like myself, he allowed me to work on which tasks I wanted to, at which given time I wanted to, as long as I met the deadlines.
The tasks were broken down to mini goals, this way my concentration levels were higher, resulting in completed tasks for that day.
Keep in mind, some have issues with confidence. Maybe even simple encouragement may help.