Standing up straight really does make you look longer, leaner, slimmer, and more graceful. The clothes you wear will look, fit, and drape better when you are standing up straight. Plus, good posture is not only great for your clothes...it's a huge boost for your self-esteem. When you stand up straight, and your back is aligned, you begin to feel taller and more confident. You even walk differently, with more purpose and elegance. Walking into a room with good posture gives you a presence.
This isn't as exciting as the fact that you'll look slimmer, but good posture is also a good way to ease and prevent lower back pain, and strengthen your core. Your carriage is important to maintaining back health, and in a way is like and instant anti-aging remedy.
Not sure how? It's easier than you think. stand against a wall so both shoulders and your behind are touching. Then pull your chin up and straighten your neck. Next put your hand between the wall and your lower back, if you're doing it right, your hand should touch the wall and your back. If your hand doesn't touch both then tilt your hips slightly back until it does. Walk away from the wall, this is what good posture looks like. You may have to practice this several times, but before long, perfect posture will become instinctive and effortless.