My advice first and foremost is talk about what you know. You know beekeeping much more than (hopefully) anyone else in the audience.
Don't pretend to be anything you're not or to talk about anything you don't know. Assume that there will be a belligerent beekeeper or two in the audience who'll try to trip you up (I've done talks where exactly that has happened) and get one over you.
Lay out the ground rules at the beginning. if people can ask questions during the talk say so, if you'd rather take questions at the end tell them. It's your talk. If people can interrupt and ask questions, don't let those questions sidetrack the talk as a whole. This is a fine art in some respects, it can indicate where your talk could have been better, it can equally let someone's curiosity derail your whole talk. If it's relevant and pertinent, answer the question, but don't be afraid to say to someone "I'll get to that later" or "Ask me again at the end of the talk".
Don't be afraid to say "I don't know". That looks and sounds better than bull....ing your way through something.
If you lose your train of thought halfway through, again, tell people. There's nothing worse than someone stood there saying nothing getting more and more flustered. 99% of the audience will forgive you if you talk to them even if you're wandering around making excuses.
If you're going to talk against slides/powerpoint:
Rehearse your talk. Do it again. And again with people trying to put you off or ask questions.
Have a dry run if you can, the first time through a talk is always the worst and it never works out right, the second time generally turns out much better.
Absolutely know how to work your kit.
Know what to do when it still goes wrong. That video might be stunning, can you still talk when it doesn't work.
Be confident. Even if it's all going wrong, the projector is on fire, wee is running down your leg and your hands are shaking so much that you can't press the change slide button, talk to your audience and tell them
something but preferably not that wee is running down your leg