Write down the key points in the conversation. If you have a reason to call someone, make sure you say what you need and the necessaries behind it. You don’t have to speak much- just make sure you know what your purpose is and are prepared to say it. So going with writing it down, with this in front of you (whether that’s a note in your phone pulled up or a piece of paper) look over the point and practice. Start with a intro- “Hi my name is ____...” then plug in why you called. “I’m calling in concern of ____...” Have any necessary notes like information for the call Incase asked so you are prepared. Once call is resolved, thank the listener and you’re free to hang up. This has been my tactic calling colleges and other professional places. For casual conversations, and even the case I just mentioned, I’d recommend having some sort of physical freedom that lets you move your body or walk around as you talk. It helps me find a rhythm and somehow get my words out better.