I hope this helps-----use a powder 3 to 4 shades darker than your skin on the outer edges of your jaw line, then on top of that add your normal shade of powder, one that goes with your skin color of course and blend. make sure its lightly so it wont be too noticeable. Use a highligter or one of those shiny powders and apply it to your cheekbones. The make up on the jaw line and on the cheek bones will make ur jawline look slimmer. I have a older sister who has a pretty square jaw and she uses this technique.