To be honest, I talk alone a lot. That's what I did to learn english, that's what I do to cold call and to give public speeches as well. You just need to get comfortable to talk, a lot, and to master the skill to make up quick, logical, thoughts and correlate them to your conversation and were you want to get it. I think the key of it is the communication skill, mostly. If you're already a good communicator, the feeling of being embarassed will fade away as soon as you make your first 30 calls (let's say), then it will get like a routine for you. Remember, this skill will help you in all the areas of your life, so I would just recommend to talk a lot. Make-up some scenarios, and try to talk your way out of the most common objections. Try asking chat gpt a list of 50 objections and try to talk them out, by speaking to yourself everyday. You just have to get used to those, and be prepared to handle them, like in every job, they prepare you for the situations you'll be encountering. I promise that once you'll get used to the idea it will come more natural than you think, to adapt quick in every situation.