Know what good posture is believed to be. Most people think that to “stand up straight” means tensing your back to heave your chest ‘in and up’, and pulling your head back in to your chest. This is not so. The spine has two natural curves that you need to maintain called the ‘double C’ or ‘S’ curves, these are the curves found from the base of your head to your shoulders and the curve from the upper back to the base of the spine. When standing straight up, make sure that your weight is evenly distributed on your feet. You might feel like you are leaning forward, and look stupid, but you don’t. (http://www.wikihow.com/Improve-Your-Posture)