Such a great little tip and so easy to forget. We were Posing training this week and one of the photographers took this shot on the left. In correcting we did only two things, pushed the weight further on to the back foot, pushing the hip back 45 degrees from the camera. Look at the difference it makes, to even a tiny frame like Deanna. The hips being forward look wider. Swapping the body language hand to the outside introduced more triangles and opened up the body and the diamond. The arm is firmly against the wall which is slimming and pulls the arm away from the body. The shoulder is anchored firmly on the wall making it easy for the client to recline towards the camera. Chin forward but not to far down on a lean face.
If you have the Posing Manual study Using the wall and all the options on that card there are 10. Girls with curves cards the best example of this is Wall recline and red dress at the window. Pushing back and away will save your hours slimming on Photoshop.