Phyllis D. answered 03/15/19
Great question!
I would recommend that at the very start of your presentation, you ask attendees to quiet or turn off their cellphones to focus on your message.
A couple of hints:
- Make this "funny" to grab their attention ("At the end of my talk there will be a quiz, so don't keep looking at your cellphones - you won't do very well if you don't listen!") or -
- "Let's work together to avoid distractions, so everyone can benefit from the information I'm about to present. The best way to really listen is to turn off or mute your cellphones. Thank you for doing this. I promise, you won't be bored!"