Just a few thoughts - softer lighting, always take 3/4 or profile shots, never head-on, use a yellow (or even orange) filter to subdue redddish skin blemishes, be aware of which side of your sitter's face is the "good" one, use a longer lens (3 or 4 times standard focal length) to flatten out perspective, use a diffuser filter or soft-focus lens. If working in b+w, be aware how very small changes in printing exposure can radically change the way skin tones look, from smooth to quite muddy and spotty-looking. And if all that doesn't work, digitise the results and retouch, the way all portrait photogs used to do when LF was the format of choice for portraits. In fact, there's an idea ...

Best regards,

David