[wantsanagent]

It is all practice. For a 30 minute presentation I might spend 6 hours in practice. Over my lifetime I've spend months of time practicing public speaking.

That said, the motivation to practice comes from success. If someone tells you you're good at something you'll do it more and be willing to spend more time doing it. Success comes from practice, so the hardest part is getting that first positive feedback if you're starting from a deficit (language barriers, previous criticism). I recommend getting a tutor for just about anything like this. Pay a stranger, whose opinion you don't care about, to get you past the awkward bits and into a range that's better than average.

Also, while some of us come off as comfortable, that doesn't mean we are.