1. Get instruction on what the proper posture is a for a dance. This is one of the first items teachers and videos normally cover.
2. Practice developing and dancing with the recommended posture.
3. It is best to have a teacher periodically review your posture. Because it is really hard to tell on your own what is wrong with your posture. Most of us end up applying part of what we were told, so the review points out were we are still off on the posture and what adjustments are needed.