thank you Mark!
i actually have a deviation on deviantart that will cover the materials question pretty well - http://robdolbs.deviantart.com/gallery/4438590#/d4ruvnl
i made that to specifically answer these kinds of questions
my fave pencils to use are definitely the staedtler mars lumographs, but as you can see in the pic i have a variety. the only thing i use for extra highlights right now is a white gel pen - i have a uni ball signo one that works really well.
funnily enough, most of the time my pencils aren't that sharp. most of my definition actually comes from blending with q tips/tortillions and using my beloved tombow mono eraser, which is super tiny and great for details!
any other questions, feel free to ask! i am happy to share