Let's start with the preparation of the oral presentation. You are supposed to be careful about the structure and logic of the talk, just as you are writing a report: What are the objectives of the talk? What are the main points I am about to make? Write out the presentation like the first sraft of a written report. Review the draft and delete things that are irrelevant or superfluous. Check the story is consistent and flows smoothly. If there are things you cannot easily express, possibly it is because of doubt about your understanding and it is better to leave them unsaid. Never read from a script. You may prepare cue cards which have key words and phrases of your presentation. Don't forget to number the cards in case you drop them.
When you deliver the presentation,you should greet your audience first. It is desirable to inform your listeners of the outline of your talk. Speak clearly. Don't shout or whisper. Don't rush or talk deliberately slowly, Be natural and make pauses at key points. You may use your hands to emphasize key points but don't indulge too much hand waving. People can develop irritating habits from time to time. Finally, enjoys yourself during the oral presentation. The audience will be on your side and want to hear what you have to say.