Delving deeper into "Introductory Sessions"

After realistically too long I'm making the leap into qualifications and a career in personal training. Honestly can't wait!

I wanted to open up discussion about Introductory Sessions, not necessarily the freebies some gyms hand out but more somebody's first proper session.

What has worked well? What hasn't worked?

Have you done more generic overall exercises or more tailored splits for them to experience what they would be getting themselves into?

Have you found that certain changes have resulted in better participation/retention?

So, long story short. Not looking for straight up workouts to copy, but hoping we can get plenty of good anecdotal information that might not only be helpful to newer PTs like myself but also experienced trainers who are always looking to adapt and adjust!