What will I have to do during the shoot, you might well ask. Follow instructions. It is up to me as the photographer to instruct you as to what to do with yourself to make you look good to the camera.
We begin with the feet. They should never be turned towards the camera as this makes them look huge. So turn them side on.
Next the legs: Weight should be unevenly distributed on your feet, with one leg bent and the other carrying more of your weight.
For women, pop your hip out, the further the better. A long photoshoot will have you feeling a little stiff the next day from all the hip popping but it looks great.
Arms: for women they should allow for negative space. This means keep at least one away from the body. For men, the arms add bulk and so can be kept beside the body.
Head: Always tilt your chin up and out (or nearly always).