Writing on paper helps me to make sense of the chaos in my head.
I have a big notebook in which I write out a first draft of new projects in as neat a handwriting as I can manage. It takes time, but it helps me to order my thoughts into something more coherent. And while writing, my subconscious usually comes up with other points that I might have missed earlier.
I enjoy making my notebook look as nice as possible, using a ruler for lines and tables, adding little illustrations in the margins when idling, etc. I want it to be something I’ll keep after it’s full, because it’ll represent a big chunk of memories from my professional life.