I have tried many different things but these seem to work the best with each Primary for getting them to quiet down and get reverent.
Jr. Primary - I start in a soft voice and say, "If you can hear me touch your knees", I make my voice get quieter and quieter each sentence saying different things like "If you hear me touch your eyes, if you can hear me fold your arms" and finally in a super soft voice I say, "If you can hear me say Jesus, or put your fingers on your lips" Whatever comes to your mind works but it's amazing at how getting quieter and quieter yourself automatically draws them in and gets their attention! I also have learned that children are wiggly, they need to move and not be expected to be 100% still always so give them a break sometime and have lots of fun songs while learning new stuff!
Sr. Primary - I simply raise my hand high in the air and make a coyote (middle and fourth finger on thumb and pinky and first finger up like ears) then I say quietly "hmmm I wonder who'll be the last to notice me a couple times while smiling! Slowly but surely everyone starts raising their own "quiet coyotes" and if there is someone that just hasn't figured out what's going on I say something like "oh welcome to Primary 3rd row boys, or thanks for joining us Rebecca!" It works every time!
I'd love to hear your ideas and what works in your Primary.