Interesting... I don't usually think about it that much. But I guess I get into a sort of "flow" eventually, where I can go for several days, imagining that I am one of the characters in my book. Then, "as" that character, I write a journal with a few quotes that would be typical for "me", in different situations. Then when I sit down to write, I have a good base around how the characters sound and are to be around.
"SHAMAN" is a action/adventure fiction novel I'm writing, following the adventures of Marcus Lee. Marcus finds a book with a peculiar symbol engraved on the cover. As Marcus digs deeper into the mysteries of the book, he learns about controlled reincarnation.
Flips back and forth between anime and a live action film. Usually depends on the mood, but often I'll visualize it both ways in the same story. I'd say seeing everything done in an anime style is most common, though.
“The most powerful weapon on earth is the human soul on fire.”
– Marshal Ferdinand Foch
I see what I'm writing as a live action movie while I'm planning or just thinking about the story, but I feel what the character would be feeling while I write. I physicalize it sometimes, to help get into a character's mindset. My mom caught me pacing around the computer room once while I was writing a particularly tense scene where my MC was extremely agitated.
"We may be starving artists, but humanity's soul would starve in the absence of our efforts".
~Dr. Michael O'Hara Associate Dean, College of Fine Arts
I also imagined characters with anime features. That is because I am a very big anime fan. I still do, but for the books that are not that strongly developed in my head. For the ones that I have them close and where the characters are not at all strangers to me, because I know everything about them from the first tooth to their wildest dreams; the images in my head mix, and become either realistic or an anime with great graphics
Normally, if I get an idea progressed enough to start to imagine what the characters look like, I'll see it in my head like a movie, with the setting, special effects and stuff and once I have that down I focus on the characters. I'll see them with their hair blowing in the wind or them in distress or love. Sometimes, if I'm just laying in bed I'll start to sort've act it out in little movements I'm freaky I know
I know that you believe you understand what you think I said, but I'm not sure you realize that what you heard is not what I meant. - Robert McCloskey
Teacher: What do we, in the U.S enjoy from places like Mexico? Student: Wait, legally?
I'm freaky I know 
