I started out by looking at a few different photos of Björn my favourite vikings character. I think he was really well cast and the actors do an amazing job. I ended up going with this straight on image that is after his fight with the bounty hunter. It shows his scar on his left cheek and I think he looks badass. I printed out that original photo as reference. 

I used the photo I printed out as reference for any shadow/highlight in this photo. I targeted the darker areas in his shadow. I did a rough pencil outline of those parts. 

After Colouring it all In I scanned it into my computer and used the live trace tool in illustrator to get my results.