Men are lucky when it comes to getting headshots.
Guys are simply held to a different standard than women, and can get away with murder in a headshot: no make-up, not bothering to shave, hair a mess, far less retouching, etc.
But that doesn't mean you can just show up and hope photoshop saves the day. A headshot for a man still has to present you favorably, accentuate the better aspects of your story, and correctly pitch you for the roles you're trying to get.
Below are some general guidelines for men's headshots.
Photoshop almost completely takes the place of make-up when I'm shooting men. The most common issue to fix is under-eye discoloration, and this is a piece of cake for photoshop. Things like moles and scars I typically handle on a case-by-case basis. If you're good at make-up by all means feel free, but keep it light (don't use a lot) and blend it well into your neck, and try to match your natural skin tone. You don't want to look like an orange. Yellow concealer is good for lessening under eye discoloration (again, I can just use photoshop) and some green concealer can get rid of excessive redness. Now, if you're thinking, "What the heck is green concealer," just come to your session good and clean - definitely shower before if you can - and don't worry about it. Photoshop is here for you.
Beards, Stubble, etc.
It depends on if the beard is part of your look or not. Do you usually have a beard? Will you have a beard when you audition? If so, you keep the beard for your headshot.
If you have stubble, then show up to the headshot with your stubble, shoot a bunch of pictures, and then go into the bathroom and carefully shave it off, then shoot a bunch of pictures without the stubble. Bring your own shaving stuff. Pick the photo you like best.
If you're normally clean shaven, the best way I have found to get a close shave it to shave in the shower. Nothing is worse than photoshopping out stubble or a bad shave. Actually, what is much worse is cutting the hell out of yourself in the shower with a razor because you haven't shaved in the shower before! SO... either practice or shave carefully over the sink if you don't normally shave in the shower. BUT... shaving in the shower is about the closest you can get to having a baby butt face.
Generally men's hair in a headshot is simple. Come in with your hair clean with no product in it if possible, but if you have a signature look then by all means do whatever it is you do.
The elephant in the room for men's hair in a headshot is hair loss. I try to light and pose men such that the face is the focus of the picture, and the top of the head situation is simply along for the ride. I often retouch hairlines a bit, but if you're going for acting work your look, whatever it might be, is what you are selling, so I don't condone do anything to present you as someone other than who you are. But I certainly will do whatever it takes to make a picture of you that you really like, and that gives you confidence and an edge in the audition.
Posing is almost always a matter of whatever makes a person look best, but in general for actor's headshots, I try to make men look commanding, and for want of a better word, manly. Now, I am about the least "macho" person you'll ever run into so what I write here is not to advance any agenda other than getting you the gig you're trying to get. So, when I am shooting men, I try to get them square, with hard lines and right angles. Squared-off shoulders, a tight, firm face, and a tall straight look overall.
Most of the way I frame and shoot you is dictated by how you look. A lot of posing is about suggesting how your body might look if people could see beyond the frame of the headshot. I generally pull back a bit and shoot more body if a man has "guns," because that does tend to be a castible attribute.
Don't Tilt Your Head!
Here is one of my pet peeves for all headshots and especially men. If I could give one piece of advice it would be Don't tilt your head. Let me rewrite that in huge friggin' letters:
DON'T TILT YOUR HEAD!!!!
It makes you look weak and indecisive. And unless you're auditioning for "Fredo" in a remake of The Godfather it's not where you want to go. Need more proof? Here are two pictures of famous guys from space:
One is the captain. The other only gets to sit in the big chair when the captain is out kicking space ass.
This is subtle: that little tilt to actor Jonathan Frakes' head weakens him. See it? You decide who you want to be.
I'll remind you in your shoot to do this if you don't. By all means keep your head straight in auditions, especially when you introduce yourself to the room.
What to Wear
The first rule is bring something you like to wear and that makes you feel good about yourself. Overall in a headshot, clothes aren't as important as your frame of mind.
Most men simply wear t-shirts with simple crew necks in headshots and you really cannot go wrong with this. Try shirts that have less saturated colors - t-shirts that have been washed a few times are better than brand new ones. And avoid busy patterns or sports team logos, writing, etc.
If you have a lot of contrast between your hair and skin (dark hair, light skin) you can generally get away with stronger color choices then men with skin and hair of similar shade. If you're a blond or redhead you have to be careful not to wear something that totally takes the focus off your face.
You have to be careful about greens and yellows. They can make you look sick (it's the way light reflects off those particular colors).
The Magic of Teal
If there is one color that looks good on virtually anyone and that works with any shade of skin it's teal. When in doubt, get teal.
These always work. Doesn't have to be exact, just get into the neighborhood.
Clothes should fit reasonably well. Excessively loose clothing can make you look overweight in a picture, but excessively tight clothing can make you look overweight as well. It depends on your body. Bring a variety of things so we can experiment a bit.
Sweaters and hoodies are useful in headshots - sometime they can add a touch of layer that can add some strength and presence to a photo.
Often I shoot men in sport jackets and with ties, especially as they get older. The reason for this is simple: many of the roles available for older men are as professionals - doctors, lawyers, etc., and a jacket and tie helps convey that message to the people making casting decisions: "Cast this guy, he looks like a lawyer." I also tend to loosen up the tie's knot a bit - sometimes it makes a person look uptight, which isn't how you want casting people to view you. I mean, who wants to deal with someone that's uptight?
Black and white shirts and jackets in headshots can be problematic. White is difficult because it tends to pull the eye towards it, and we don't want people looking at your shirt, we want them looking at your face. Black can do the same sort of thing, and wearing a black jacket with a black shirt and a black tie can make a photo stiff and charmless, and somewhat threatening. It might be a look you're going for, especially if you're pursuing roles in crime shows, but it can be heavy and ponderous in a general use headshot.
Collars: In general, with t-shirts, you want to try to match your collar to your jawline. So, if you have a squarish jaw, you should wear a squarish collar. If your face is more V-shaped face, a more V'd collar tends to work better. Often this doesn't apply - most men simply buy clothes, but there are times when a shirt just doesn't look good and often its the collar.
Collared shirts function by opposite rules, and generally you want a collar that does the opposite of your face. So, if you have a long face you'll do well to wear a wider collar, as a narrow one will make your face appear excessively long. Beware of small collars if you have a wide face or a big head however - they can make your head look tiny in a picture.
Pants... you don't really need to worry about this in a headshot. I mean, yes, please, wear pants or shorts, but chances are they won't be in the shot so it doesn't really matter what is going on from the waist down.
All this being said, generally anything you wear can work so don't drive yourself crazy. Pick a few shirts and come to the shoot.
I don't like excessively retouched pictures and neither do casting directors. Ultimately your photo has to look like you and I retouch it so that it looks like you on a really good day. Generally, for a man's headshot, this means brightening up eyes and teeth a little bit, cleaning up minor skin issues (under the eyes, red around the nose, chapped lips, blemishes) and getting rid of fly away hairs.
Sometimes I'll do some reshaping to square the image off a bit - fix sloping shoulders, get rid of wrinkles in clothes, pull in ears a tiny bit, diminish facial wrinkled. etc. I try to do as little as possible to make you look as much like the best you possible.