Along those same lines, there are guidelines for posing a portrait subject. While there aren't any hard-and-fast posing rules, history has demonstrated time and again that there are a lot of poses that are more likely to lead to good pictures, and some that are just as likely to result in bad ones. So, without further ado, here are some of my own favorite posing "rules" that I've found lead to better portraits.
For headshot portraits, I usually like to seat the subject on a stool or low-backed chair that offers firm support and a very upright sitting position. This helps to keep them fairly stationary and stable, and you can give them directions to fine-tune the pose pretty easily. I almost always want their shoulders turned toward a 45-degree angle away from the camera in either direction, with their head facing me. Too much shoulder turn, however, can make a thin person all but disappear. A slight tilt of the head in the direction their shoulders are facing creates a more focused, engaged-looking subject. It's a stronger look than if the head is tilted away from the direction the subject's shoulders are facing, which inherently appears softer and more passive—meaning it may sometimes be the perfect head position for the look you're after.
Many subjects are self-conscious about the appearance of a double chin. Consequently, you'll find that they often hold their chin up too high. To get their chin down and help hide any hint of a double chin that may appear, ask them to bend forward at the waist. Bending very far, to the extreme, while maintaining eye contact with the lens will demonstrate the principle at play, elongating the neck and avoiding any double chins. You likely don't want them to lean in that far, but you'll get the idea of how the chin fix works by asking the subject to exaggerate their lean. A subtle lean in also helps the subject appear engaged with the viewer.
Sometimes I'll place an apple box on the floor in front of my subject and ask them to put a foot up on the box, bringing their knee up in front of them. They can then lean their elbow on their knee, which creates a more casual overall appearance—and almost always positions their torso, shoulders and head in an attractive pose that creates nice lines and angles. It's a great way to keep a seated portrait from coming across as too stuffy.
If I'm photographing someone obese, I don't like to seat them. Sitting poses can exaggerate the weight around their face and neck. Instead, I ask them to stand and use many of the same posing guidelines I would if they were seated.
With standing portraits, I still want to avoid a subject squaring their shoulders to the camera. I find that the biggest problem is a subject appearing stiff and uncomfortable. I tell them they look like they're standing at attention and we'd rather they look at ease. To accomplish this, putting their weight on one leg or the other changes the dynamics of their pose dramatically. It affects their torso, shoulders and head positions in usually wonderful ways, and you can often see the comfort of the pose reflected in a more relaxed look on their face and in their eyes.
I will say, though, that some folks have a hard time getting their weight onto one leg or the other, and it can be quite amusing to watch them lift a foot as they try to determine exactly what I'm getting at. A shortcut to aid their posing can be to give them something to lean on—a wall, the back of a chair, or even a tall stool on which they can half-sit. I tend to see scene elements like this as anchors for your subjects, giving them something sturdy to hold on to. It helps avoid the look and feel of a deer in the headlights, not sure exactly where they are or why they're standing this way. Regardless of how it makes their body appear, it's sure to be evidenced by a slightly lost look on their face—something almost impossible to overcome unless you can get them into a pose that feels more comfortable.
Be careful of making a pose too comfortable, though. Often you'll hear feedback from a subject that a pose feels unnatural. I like to tell them that as long as it looks good it doesn't have to feel good. "After all," I say, "have you ever seen yourself when you're really comfortable? You're probably slouching on the couch. And that probably doesn't look too good." We want them just comfortable enough, but not too comfortable.
The next item in need of attention for your subject is likely their hands. "What do I do with my hands?" they ask. I believe that a subject standing comfortably with their hands at their sides looks calm and confident, strong and powerful—which is probably why nobody seems to stand this way naturally. Watch your subjects clasp their hands in front of them, or fold them behind. This is almost always a nervous reaction to not knowing where to put their hands. When in doubt, let them hang comfortably at their sides. They will feel exposed, but they'll look calm and confident.
A hand in the pocket, hands on hips or arms folded can be perfectly natural and comfortable poses that give your subject something to do with their hands. Watch out for folks who look like they've never stood that way before. If a subject isn't a natural arm folder, you'll know. They'll look uncomfortable and unnatural. Don't force it.
Arms folded can also be a bit of a standoffish pose. A little too authoritarian and a little too tough, unless the casual nature of the rest of the scene, the remainder of the pose and the subject's expression counteract this. Either way, be wary of overdoing the arms folded pose as it can become a crutch for when you don't know what to do with your subject's hands.
Hands can be tricky, too, if they're positioned incorrectly. Fingers spread out rarely look good. Folded softly, curled around an imaginary pen for instance, or shown from the side tend to make more attractive an unobtrusive use of their hands.
Some photographers are fond of resting a chin or a cheek on a subject's hand. I'm not particularly fond of this technique, though it does have its place. If you do put a hand on the chin or cheek, make sure the subject knows they're not actually leaning their weight on it. It's just supposed to create the illusion of support. If they really lean their weight on their hand they'll smash their face a bit, which is rarely attractive in portraits.
When in doubt, watch how celebrities pose for portraits in situations where they aren't specifically working with a photographer. The red carpet is a great place to see classic posing guidelines in action. Hand on hip, slight turn, tilted head, a toe pointed just so in order to create a leading line… You'll be studying from some of the best.
Similarly, if you get in a rut and find yourself using the same old poses over and over, it can be helpful to consult a "look book" of poses you've assembled ahead of time. Mine is comprised of clipped photos from magazines and catalogs, and some simple sketches of poses I've found work well. Sometimes all it takes to find the perfect pose is to do something outside your comfort zone. Look for poses that include full body and close-ups, standing, seated and even laying down—a type of pose that isn't for everyone, but when it's appropriate (model headshots or senior portraits, for instance) it can be a very flattering look and a unique end result. It can be casual or glamorous, light and fun or sexy and sensual. The point is, to pose someone laying down you'd better have a fairly particular agenda in mind. This type of pose serves as a reminder that it's important to choose poses that are appropriate for the subject. A glamour pose on a corporate boss isn't likely to be ideal, nor is a power-pose going to sit comfortably on a child. Poses, like every other element in a scene, send messages. Choosing them correctly is the only way to ensure you're sending the message you intend.