If you feel that doesn’t work, then I would advice to get a brace. It’s not the sexiest thing in the world walking around town with a brace underneath the clothes. Yoga, Pilates and Ballet are very good posture improvers.
Wear something form-fitting and take two full-body photos—one from the front, one from the side.
1 / Look at your ear. If it's in front of the midpoint of your shoulder, your head is too far forward.
2 / Can you see your shoulder blade? That means your back is too rounded.
3 / If your hips tilt forward and you have a belly pooch (even if you don't have an ounce of fat on your body) and your lower spine is arched significantly, this means you have an anterior pelvic tilt.
4 / Look at your shoulders. One shouldn't appear higher than the other.
5 / Check out your kneecaps. Do they point inward, causing your knees to touch when your legs are straightened?
6 / See if you're duck-footed. Your toes will point outward more than 10 degrees.