Ah, depends on the child!

But for kids over 8, a nice long form video works well. That, and having enough time so that they don't feel like we're in a rush, but also not taking to long to load them onto the scanner...

For the younger ones, it's very much dependent on the child. So we take a bit of time to get to know them before we get them to attend. We have videos to prep them, and can follow a script when loading them (e.g. becoming an astronaut and blasting off into space...).