I started with below sketch, which is mainly based on a publicity still of Yvonne Craig (the working at my desk and covering the drawing surreptitiously every time someone came into the room.... I guess I've been doing that for years, doodling in class, at my desk, anywhere where I should be doing something else.
Once I got home I scanned the above and then reprinted it in very light red, at about twice the size of the original. I drew over the red print in HB lead and refashioned many details. When I rescan the image I can filter out the red completely, leaving just the clean pencil lines.
A lot of illustrators, especially in comics and animation, use this technique when making rough drafts, although they generally work with "no-repro" blue or red pencils. I find that the waxy pencils are frustrating to draw over, so I usually will use the manipulation technique. Which also allows me to keep a lot of the energy of a small drawing by just scaling it up.
Here's the next draft. No cape yet, still trying to figure it out. The final draft will most likely include a chimney festooned Victorian skyline.