Someone told me once “you have one mouth and two ears, that means you should listen twice as much as you talk.” This has with me for over 20 years. As an LT, I would add eyes in there too. With that, listen to and watch the leaders that you consider disciplined and follow their lead. Learn from others mistakes. You will hear about them. Be great at the easy stuff: Be early, be organized, do PT with your Soldiers, have your NCOIC check your equipment before you go to the field/range/training, ask questions and verify the answers. Change the stuff you can and try to influence the things you can’t.