Beth P. answered  07/13/22
Experienced Teacher and Tutor in English, Math and Science
I would suggest working with an excellent outline that you know solidly. Then you can add details as needed.
Pretend you are sharing this topic that you know well with a person you trust or care for with about the same knowledge level as your audience. If it is a professional audience, that person might be a close colleague. If it is a general audience, that might be a friend. This tactic will ensure you are speaking directly to the audience.
Remember that your love and interest in the topic will communicate. If you aren't interested, no one else will be either!
And then basic stuff: speak slowly, clearly and loudly enough. Make eye contact. Don't read completely from a script. ( You may find it helpful to use some prepared phrases, but not the entire presentation.) Remember that most people read faster than you can speak, so if you are using a powerpoint with details, don't read all of them. Generally powerpoints should only have key ideas anyway to help the audience grasp the big picture for each point.