Positioning on a Chair - This is critical. When someone sits normally in a chair, they put their butt back and most of the weight of their body rests on the thighs and butt. This flattens both. Instead, have them sit on the edge of the chair. This minimizes the distortion, and then when you have them cross the near leg over the distant leg, you don't have that flattened out upper leg that can ruin the pose and image. Also, look at the lines in this image. All lines lead to the face.