With my trusty cyan maquette and my PITT pens, I've been slowly adding ink to the Tomb of the Timeless Master. There are quite a few rooms, so I've annotated my SketchUp drawing with notes cribbed from the module.
At this point I'm grateful for the copious perspective-reference lines I sprinkled all over the maquette. For irregular structures like rocky cliff faces (which are really just scraggly lines), it's really easy to destroy the sense of perspective without constant reminders of the 3D space they're filling.
Once I've filled the page, I scan it into Photoshop to use its magic to pull out the blue lines, and clean off any crud.
To add more to the illustration, however, I add a blue gradient map, so that I can use what I've completed so far as a structure to attach the rest to.
Time to stock up on cyan printer cartridges!