You can get each of these for free. But they each make a world of difference in your personal life, professional life. If I had to pick one of these items that has an immediate impact and is relatively easy, I would work on body language. Shoulders back, take up space. Hunched over a keyboard (which is what you are doing now if you are like me. Shoulders back, sit up straight 😉) is a naturally low power position. When you have to speak before a group don’t shove your hands in your pockets. Set your feet a little wider than normal. Smile. These will make you feel better personally, and make you appear better to you others.
We can do this!