You should always have pen and paper ready to keep your attention focused on what you are trying to do: learn something. Actively. Which means with all the tools at your disposal: mind, feelings, eyes, ears... and fingers complete with pen or pencil to note down new words, ideas, objections, questions or just to doodle. So a print-out would not be a bad idea, an all-purpose tool. Highlight problem causers, practice words and structures, annotate.