How to convert a drawing to vector in Illustrator

A very very helpful and informative step-by-step youtube lesson by TastyTuts (haha love the name)
I shall try this very very soon! :)

Color proof

About to launch these bad bois to my online shop but the color seems to be a little off compare to the original ones. Hence, I'm testing it here before listing! 
Let me know what you think :)