LEADING UP TO YOUR HEADSHOT SESSION
Do not get your hair cut on the day of your session, or even the day before. If you are planning to get a new style, do it a couple weeks before your session so you have time to get used to it, and practice styling it.
Drink plenty of water on the days leading up to your session. The more hydrated you are the better your skin will look. You cannot do this all on the morning of your session -- start a couple of days before!
If you suffer from dry, cracked lips, start using plenty of lip balm from a couple of days before your session to make sure your lips are nice and hydrated. Dry cracked lips can be photo-shopped, but it's better to just have it right in person.
CLOTHING FOR YOUR SESSION
This largely depends on the purpose of the headshot session and is different for men and women. Depending on your industry things may be a bit more informal as well; no-one at Google seems to own a tie for example. I recommend looking at LinkedIn and see what the standard is for managers in your chosen industry, but below are some guidelines:
For a traditional corporate headshot, a white shirt, tie and dark grey or blue jacket is a classic look that is hard to beat. For anyone in finance or sales of any kind, this is what I would recommend.
Do not worry that a suit is 'boring' or 'stiff'. Personality comes from your face, not your clothes when you wear a suit.
I would strongly recommend a Windsor knot for your tie; it is a much smarter looking knot. If you do not know how to tie one I can show you!
Things are generally a bit more relaxed for women, but I recommend you dress smartly, as you would for an interview or important client meeting.
You do not need to wear a jacket, but it can be an effective look for some industries.
MEN AND WOMEN (NON-CORPORATE)
Creatives, small business owners, university lecturers and anyone else that doesn't need to wear a suit and tie everyday, you can wear whatever you wish, but would recommend against busy patterns, even on ties.
Above all else, the most important thing is to feel comfortable in what you are wearing. If you do not feel comfortable you will not look comfortable.
If you absolutely hate wearing a tie then I would much rather you go without and look relaxed and confident than wear tie and look miserable.
Feel free to bring changes of outfit, but be aware that more variety isn't always better. It is generally more productive to focus on shooting than spending time getting changed over and over again. I would not recommend more than two outfits during your session.
Also be aware that for a headshot, only the top few inches of your clothing are visible. Please feel free to wear tracksuit bottoms with your suit jacket, shirt and tie if that makes you feel comfortable!
HAIR AND MAKEUP
Style your hair as you usually would and you're done. Easy!
Good lighting and Photoshop go a long way, so please don't feel you have to go overboard on the makeup to achieve perfect skin. Removing blemishes, redness, pimples, light wrinkles etc in Photoshop takes seconds. You do not need to cover them with a lot of foundation and/or concealer.
Do your makeup in the same way as you would for an interview or other important meeting. If you normally wear no makeup then feel free to wear no makeup. If you have freckles then show them off!
We feel that strong makeup on a business headshot can look a bit out of place. Often the best makeup is a fairly natural look, with foundation closely matching skin tones. Use subtle lipstick (ie only one shade lighter or darker than natural) and no strongly coloured eye shadow.
At the end of the day though, makeup is like clothing. Wear what makes you feel happy, relaxed and confident. That is what's most important.