1960s makeup looks run the gamut from natural to up-to-your-brows in shimmery blue eyeshadow and a crapload of black liner. The Star Trek original series had a heavier makeup look overall (even for the men). Therefore, I went for a combination mod/blue eyeshadow look.
And a wig! I wasn’t willing to submit my hair to the Dippity Do, hot rollers, and back-combing necessary for a good 1960s look. I got a wig that was close to my natural hair color so the portraits would make visual sense.
I’d give detailed advice specific to how to achieve this look, but there are numerous youtube videos and step-by-step instructions out there by good makeup artists. Overall, I’d say to use a heavy coat of a good quality foundation and light eye primer. Also, make sure the lip is a nude or light natural color so as not to distract from the eyes.