From the thumbnails I've decided what I think I need for the characters, so the next step is to draw them out in simple form. As I said before, I don't want to make this a step-by-step instruction for how to draw the Master Chief but I'll try to put some tips in that I've found valuable.
Click Thumbs to see larger images.
I don't normally do multiple versions of a character, but for the purpose of this guide I've tried to show how I start at a basic level. I keep the drawings very loose and messy because I love to pick up on the accidental marks that tend to come up when going fast. Don't overthink any area and bring the whole drawing to the same level of detail at once. It makes for a more balanced image and you dont waste time putting details into something that might be the wrong!