Firstly characters: how they will look, what they will be wearing and later how they will move. It is hard to imagine movement before we have established the personality and apperance of the characters.
So first rough sketches and next we develope our characters and finally we know how our character/s look like.
This is my characters for animation.
Later we create character sheets. Can be in color or black and white. It is better when we see character, at least, in 3 viewa. Ofcourse can be more. Every time proportion of the body need to be the same.
On this site there are lots of character sheets and it is good to see how professional artist make them.
I also reccommend the book "The Art of Hercules: The chaos of creation" S.Rebello and J.Healey. There are pictures of characters how they looked at the beginning and how they developed them.