When I start a girl I pencil her in with Prisma color Col-erase colored pencil in black. Then I go over the lines with a fine point water based Sharpie paint pen. The background is gesso and acrylics. This makes for a smooth drawing (and erasing) substrate.
The eyes are my biggest challenge. The face. Here is "J". I started her and am trying a new skin tone with gellatos.