Body posture for aesthetic reasons

I know that posture is poorly correlated with pain, but what about when a person wants to “improve” it for aesthetic reasons, e.g. stop hunching? What is your approach then?

The posture you describe is often volitional, i.e. the person can adopt a different posture without specific training or coaching on their own. Cues can be sometimes be useful, whether they’re physical or mental. Also, training the areas involved in the posture change can sometimes “improve” the default adopted posture.