To your arsenal of storytelling techniques add gestures. These additions to your visual aids can do much to keep the children's attention as well as communicate. Don't forget - you are your best audio-visual aid!
Gestures can be used to demonstrate what someone in the lesson is doing. Example: When the disciples are distributing the fish and bread, make as if you are doing the same.
They can also be used to show how someone feels. Examples: Pulling on your hair to demonstrate frustration. Putting your finger to your head as someone thinking.
Or you can use a gesture as you address the children directly. Example: Gesturing with your hand towards the children as you challenge them, "Will you...?"
Pointing, shrugging shoulders shaking your head and just about any other gesture you can think of can be used not only as an expression, but also to instruct your children in a way that is more visual and, if you can get them to follow you, a way that can be more participatory as well.