So, what does that look like? I'm either staring at a blank wall with a distant or (I've been told) angry look on my face, or I'm standing in the shower. Sometimes, I might be walking around having a conversation with myself. Yes, I both talk TO myself as well as ANSWER myself.
It's kinda hard to just let go and enter my imaginary world, especially if I'm tired after working all day, but caffeine and loud music seem to help.
And another thing - that's why it sucks when the music changes! If I can feel my story out when a certain song is blasting through my head, the whole mood is shot if the music changes!