Ever since the 30's most tables and schematics were drawn on sheet canvas or newly invented vellum. All work was methodically drawn by hand with pencil or India Ink. Circuit diagrams, metal stampings, springs and the immortal electric bumpers all came from rigid engineering standards. Games were completed faster than today, but those past pinballs were far less complex. The hardest and fundamentally most important design choice is the theme to begin with.
Every game starts there and in some cases ends there too.
A poorly rendered theme can trash a game's success. On my design team we use universal topics or concepts. Every tidbit is written down in my master book, one for each game, so nothing gets lost. Concurrently I begin a new Autocad drawing, laying out the main playfield. The whole game is rendered this way and layers are created for all parts on a typical playfield.