I sometimes do children's music at festivals, and I agree with R&W Rabbit that 'advertising' is key!

I've done workshops where they've used the title/description I've given them, and had a nice group show up.

I've also done workshops where they describe my event as "singing." Well, who's going to come to that? Not many...

It's helpful if you can have ways for the children to actively participate.

:^)