Dialogue
This page is still a work in progress.
Speech tempo
When the story has an invisible (acousmatic) virtual character talking, obviously the user cannot see their body language and expressions. If the character's natural speech tempo is slow, the user may get bored since it's impossible to look at and interpret the talker's face and body language. Hence, it may be beneficial to let the actor talk faster. Or try to adjust the speech tempo afterwards.
Use of narrator describing events
Probably not the most characteristic of 6DoF AAR, but an interesting narrative technique would be to have a narrator or characters comment on events happening in real-life or describe invisible events.