This seems like a pretty dry topic, and I’ll provide some basic tips in a bit, but I’d like to start with a suggestion that might not seem so obvious: Prepare to have fun.
What? Fun? Headshots? Isn’t there a formula or something? Well, sort of, but as much as lighting and clothing matter, what really makes a portrait is active involvement on the part of the subject, and if it’s not there, the photographer can’t Photoshop it in. Even when the goal is a business-like demeanor, if you’re having fun doing it, it shows up in your eyes and the relaxed appearance of your face in a way that presents you as someone who’s accessible, self-assured, and interesting to talk to.
Think of your portrait session not as a trip to the dentist, but as play time where you can invent, like an actor, the character you want to present. That character may or may not be who you feel you really are. You might be a party animal who wants to look “respectable”. Or, you might be a shy person who wants to look like a leader. It’s up to you. The key thing is to realize that your mental image of yourself doesn’t encompass all the versions of you who actually show up in all the various moments of your life and that you can choose whichever version you want to show. Have fun with it, and your portraits will really look alive.
As for the rest, here are a few practical nuts & bolts tips.
Choose clothing that matches the character you’re playing. A bit of color can help, even if your character is conservative. For clothing that is close to your face or next to your skin, choose tones that are somewhat, but not radically, lighter or darker than your skin tone. No white shirts on anybody, and no black shirts on light-skinned folks. Avoid wearing white as an outer garment, as this will vanish against a white background and glare against a black one. Keep patterns simple and subtle unless you’re going for a “wild” look. Avoid clothing with large blocks of text on it. Wear shoes in which you can stand and move comfortably - tippy stilettos may make it hard to relax, especially if you’re on soft carpet.
Makeup looks different to a camera than to the naked eye. Bright colors may appear stronger in a photo, so if you wear makeup, tone it down just a bit compared to your target look. If you’re using foundation or powder, keep it subtle and pay particular attention to taming bright spots on your nose, cheeks and forehead. Even without anything else, blotting paper and a little powder can make a huge difference. Your photographer will try to minimize bright spots by using soft lighting, but shiny skin is one of the biggest technical challenges.
Useful things to bring -
That’s it. Let’s play!