Before I begin writing a story, a lot of time is spent mulling over plot and characters in my head. It is when I begin to think about who goes with the two main characters. I work out the difficulties they will face and come up with subplots. For me it all happens before I begin typing. Once in awhile I might write a vignette to help me think about the mood of the piece-- the snippet often won't ever make it into the book.
In the historical story I am currently planning, its two lead characters will be different than any I've written-- both are warriors in different fields. I've written about heroes who had been in the military and about lawmen but never a career military officer. To add to the difference, my heroine will also be in a business that required secrecy and involved danger. She will be able to shoot and react as well as a man when required.
Two warriors. And me not a warrior. Well, I've been listening to documentaries, reading things, to get the feel for what that means. Music is a factor also and the following video is about warriors over a period of generations. There are no images-- just words about a desire for peace while one straps on a gun to do their part to bring that about. I have to get the feel for a world in which I have never lived in order to tell the story that has come to me this time.