Practice in VITAL! I recommend speakers practice a speech 10 times--then present to the mirror, the cat, their grandma who doesn't speak English--then record themselves and listen to the recording over and over. We all need to build fluency!
Watch many examples. We think we know what good speaking looks like, but do we? College courses require presentations, but students are scored on delivery of content, not audience engagement.
Build in opportunities for low-stakes, impromptu speaking.