Be confident and show the confidence to your audience
Show enthusiasm! If the speaker appears to be not so interested, how can you expect the audience to become interested?
Face the audience, keep eye contact
Voice: change the speed, tone, and volume according to the content. For example: slow down for the important or complex part, louder for the exciting part.
If no microphone is available, make sure to project your voice to the entire room
Be careful with the pointer. Use the pointer to help the audience, not to distract them.