After exploring seedling ideas in my sketchbook, I start to work out full drawings using tracing paper. Tracing paper is cheap and abundant and encourages experimentation. Expensive papers can induce anxiety, make you fearful of making mistakes. Using inexpensive tracing paper alleviates that anxiety, allowing you to loosen up and play with your drawings.
And when I run into visual dilemmas, because the tracing paper is transparent, I can experiment, overlaying drawings to find solutions. Once I have a drawing worked out on tracing paper, I photocopy the drawing, or scan it, so that I can then make an "old-fashioned" paste-up book dummy.