Charcoal of this form is a challenge, and the ribbed texture of Fusain paper's adds to it. One has to master that subtle touch of the charcoal against the paper to get that effect you want. Once you have that accidental smudges you cannot forgive yourself because it's hard to erase them. You end up adopting them to something else and make them part of the equation. Careful with your hands and sleeves.
One of the artists I've seen in youtube has a little notebook he uses on the side where he has a tiny study drawing of his subject and some notes with it. As he starts his drawing he already has a plan laid out. I think that's a great and smart idea. Although it's not a common practice, but it is a great tool to remind you of the things to be done, saves your time figuring out what to do next. I like the idea of keeping you on track to your goal, and not going by your instinct as you go along. It's more driven purpose.