Torso Posing Rules
Straighten your Back
Avoid slouching. Instead, straighten the back, which will make you look taller, slimmer, and more poised and confident.
Relax your Shoulders
Hunched shoulders hide your neck, making it appear short. Your shoulders should feel relaxed. If they aren't, reposition yourself by straightening your back and rolling your shoulders, letting them relax at the end while maintaining an upright posture.
Drop the Shoulder Toward the Camera
Although relaxed, the line through the shoulders should be at an angle to the camera to give a more dynamic appearance. Drop the shoulder that is closest to the camera, which will open and smooth the neck.
Angle your Pose
Turn your body so that the line of the chest and shoulders is one a slight angle with the camera. If the chest is flat to the camera then you look broader and more imposing, so turning a bit makes you look slimmer and more friendly.
Sit on One Hip
This is the seated version of the Weight on the Back Leg Rule. When sitting, put your weight on one hip rather than centred on both of them. This lets you roll the hips, creating a variety of seated postures. Roll the hip up from the seat and the result will be a slimmer look.
Flex your Stomach
Just before the photographer takes the shot, flex your stomach muscles to give yourself a more toned appearance.
A tip for photographers: It is difficult for models to hold postures for long so get in the habit of counting down the shot. As a side benefit it will force you to slow down (avoiding the "rapid-fire" technique) and prepare for each shot. You can use the count-down to do a last minute check of things like lighting, background, and details.
Use your Cleavage
If you're a female model, chances are you'll be using your cleavage to your best advantage at some point.
When leaning forward you can bring your arms together at the waist, keeping your arms straight at the elbows while clasping your hands together below your waist, or you can just cross your arms. The first model shown here is simply bringing her elbows together to create the same effect. This is a situation where slouching may be to your advantage, but in limited quantities and only where the cleavage will be the focus.
When leaning backward you can raise your arms about your shoulders and head, keeping your arms apart.