Early instructing experience
Study and learn the FOI. It is not just a bunch of gobbledegook to regurgitate for the CFI practical, it is knowlege and a manual to live by, a way of life, for flight instructing.
I remember that during my first few hours of instructing I knew what I was doing but didn't feel that I had my shtik down. I was teaching a bunch of young pre-solo CAP cadets. I was teaching the same thing three or four flights a day. It gave me a great opportunity to hone my explanations.
I probably was the world's worst flight student. So, it surprised me how quickly my students picked up what I was teaching them in comparison to me learning it. I also remember soloing out my first student. I knew that he was ready, but was I? So, I signed off his student certificate and logbook, stepped out, and sent him on his way, wondering, what if? He did fine, but I suspect that I was more excited about creating a new pilot than he was about soloing.