How to better impress in phone chats?

I am not sure if I am the only one who suffers this issue. If I were meeting up someone for a coffee, then even if they are of a senior role I am generally very good at interacting with them and being able to impress them with fast thinking and overall confidence. However, when I am calling them, I usually am a lot more awkward. Conversations feel a lot more forced, and I have to rely on pre-prepared questions and can't really spontaneously go with the flow of the conversation. Just wondering if anyone have any tips on how I can conquer this issue, particularly since as a rising sophomore, I realize that most first rounds for SA recruiting have been formalized to be phone rounds and I will need to get better at calling.