In your note book list the things that you think you could improve with your posture and demeanour. Ask those trusted to you to share what they see. “We cannot change what we can’t see”
Next to them note the benefits for you by improving them.
Pick one at a time and work on it until you feel you have created a new habit. Then move on to the next one. Don’t try and work on more than one thing at a time as you will not successfully do any of them. The new science is that multi tasking does a few things with mediocrity and none well.
Is this something you could add to your 12 month plan?