When I first start out I have a nice normal picture of my main character fixed in my mind, the stereotypical all American girl. She usually has long hair of a natural color like brown or blond. Her skin is typically pale and freckle free. In fact her skin is free of everything. No piercings or tattoos in sight just pristine white skin, much like mine. Even her clothes are plane with a t-shirt and jeans being the norm.
Then as I start writing I get to know her, and my mental picture of her begins to change. The jeans normally stay exactly where they are, but the shirt is usually the first thing to be replaced. Then hair gets shorter or longer or curlier or straighter, and a little color splash or two might get added along the way. A tasteful, or sometimes not, tattoo, or five, blossoms somewhere on her person, and sometimes a little metal slips it’s way in at the same time.
The last thing to change is the whole “human” thing. They may be human part of the time, but for some reason my characters just can’t seem to stay that way all the time. By the time I start writing they’re either more or less than human. Shape shifting, curses, supernatural forces, magical powers whatever the device it’s the ultimate body mod.
So, how does your characters’ appearance change from first glimpse to final draft?