I went out for a walk and drew some trees with charcoal. I'm trying to overcome my fear of drawing in front of people. Every time someone passed by I twitched and tried to hide my drawing :/
Anyway, white pencil over charcoal gives an awful result (as seen of first picture) so there shouldn't be even a little charcoal on the parts to be highlighted... blah.
They got smudged a bit before I got home to fix them with a hairspray.
Charcoal pencil on A4 yellow textured paper. Around 15 minutes each.