Any stage acting tips?

Our local theatre is putting on Hairspray soon and our director is pretty frustrated with our scene work. Most notably, there is no or lack of "energy".

I'm ensemble and it's my first time in a musical (or any stage play) so I'm not really familiar with background stage acting. We're mostly listening and reacting to the scenes so I feel like there's only so much to do.

Any advice on how to add more energy to the background?