Hi Kristin:
Sometimes reengaging can be simple, like just begin asking questions and having the class discuss the students responses. Or simple, like "stand up, stretch, okay, sit down and let's get back to it".
Other times takes more effort, even including change ups -this where we swith gears altogether. So if lecture with PPT and whiteboard is not keeping the attention and focus, change up to something else, such as a class activity such as work sheets or written work, or if applicable, a lab or skill activity.
In the middle might be sharing a story, anectdote, or work… >>>
