One truly important self-development habit that I was taught by my father is to make random comments to anyone that you may meet throughout your life. No matter if it may come off as awkward, just doing it will allow you to say it better the next time around.
Too often, we miss out on the opportunity to connect with one another. Grab hold of the opportunity and speak your mind. Not only is it practice for the next person you talk to, but it also strengthens your own voice.