To become better, you need experience, people say. And it's true. But how do you get it? And how do you get as diverse of an experience in speaking and presenting as possible?
Ask - working in a company? Talk with your manager or someone else from the comms team, for example, and see if they are looking for someone to present on a topic you can. If such - do it.
Create - no opportunities? Then create them yourself. Pick up a topic you love speaking about, organise the people around you to join and listen to you and present it to them. Possible? Perfect. Seek feedback afterwards!
Discover - no options in your company at all? Then search online for communities - user groups, smaller events (online or in-person), conferences and submit ideas to them. You'll be surprised.
The more you do, the better you get. The better you get, the more confident you become. The more confident you become, the easier it all is.