[Callers] Rolling Starts?

I think that rolling starts (seamless transition from walkthrough into the dance, as the band just starts playing music during the walkthrough) are super neat if done properly! But I'm still not quite sure how to do them properly. So I ask you all: 1) tips on how to execute a rolling start well, making sure all the dancers are on board etc.? 2) thoughts on what dances/tunes will/won't work well with a rolling start? Cheers, Maia