Many years ago, when I taught accelerated ground school, I had to ensure that every student knew the essential ideas in any of the lectures I presented. To do this, I used the communications strategy of one old-time TV evangelist. When the preacher wanted to get someone's attention, he'd precede his important statement by saying, in a purposeful and commanding voice, "Now, listen to me."
The secret to making this work is telling your student or the audience beforehand that when they hear the words, "Now listen to me," it's the Nugget Notice. They should shut off the channels dealing with food, TV, the opposite sex, and anything other than what you're about to say. I still use this strategy with large audiences or in the cockpit. Of course, you can use any phrase that conveys a similar meaning.
Now, listen to me. Convey your message with importance by letting your students know it's important. Give your students the Nugget Notice, then deliver the message.