1) Think about what you like and what’s cool or interesting to you.
2) Establish the character and environment. Paint yourself the picture, know the story, know their story.
3) Research subject matter for the tone, mood, feel. For example: For a Viking character you would research the lore, dress, weapons, life-style, traditions, ships, landscape.
4) For follows function, every design choice should lead to a story or a character trait.
5) What’s needed for this character in order to tell the story for the sequence and for the shot. Props, vehicles, super costume, utility belt?
6) What’s their background, where did they grow up, who are they friends with? What do their parents do?